TaxGPT Cowork prepares a review-ready Form 1040-X from the original return and the corrected documents that triggered that amendment.
Amended returns are the work nobody schedules: a corrected W-2 shows up in April, a late K-1 lands after the original was filed, or a new client arrives convinced the prior firm missed a deduction. The 1040-X can't start until the original return is reconciled line by line. When the original was filed from other software, re-keying it can take a senior preparer's day before the amendment even begins.
This guide shows how Cowork runs the full workflow: it opens the original return in your tax software or rebuilds it there from the filed copy, verifies the as-filed Column A amounts, enters the changes you specify, and produces a draft Form 1040-X with a review workpaper and the Part II explanation of changes you approve.
You stay in control. Cowork prepares the return through final diagnostics. Your firm reviews, signs and transmits. Cowork will not e-file, e-sign, email the client, print, or overwrite the original return without your explicit go-ahead.
What do I need before I start?
Access to TaxGPT Cowork
The original return in your tax software or, if it was filed elsewhere, a copy of the filed return or an IRS transcript, along with the original source documents if available
The corrected or newly received documents driving the amendment
A short description of what changed and why
The tax year being amended
Your tax software and its credentials (Cowork needs a platform skill installed for that software)
How does Cowork prepare an amended return?
You give Cowork the client, the tax year, your tax software, the reason for the amendment and the documents necessitating the change. One question sets the path: was the original return prepared in your current tax software?
PATH A: ORIGINAL IN YOUR SOFTWARE | PATH B: ORIGINAL FILED ELSEWHERE |
Cowork opens the original return in your tax software, confirms the client and tax year, and adds Form 1040-X to it. | Provide a copy of the filed return or an IRS transcript, along with the original source documents if available. Cowork re-enters the as-filed values in your software as a baseline, then checks it against your document on AGI, taxable income, total tax, payments, and refund or balance due. It stops on any mismatch before adding Form 1040-X. |
On either path, Cowork then verifies Column A against the as-filed return for every line the amendment will touch. If any amount doesn't match, it stops, shows you the line, the amount found and the amount expected, and waits for you to resolve it.
Next, Cowork drafts the Part II explanation of changes from the reason you gave. Once you confirm the wording, that confirmation also confirms the work Cowork is expected to complete. Cowork then enters the changes you specify in your tax software, which recomputes the return, and builds a review workpaper showing Column A (as originally reported or previously adjusted), Column B (net change) and Column C (corrected) for each changed line.
Cowork doesn't decide what to change or how to resolve discrepancies; it brings those decisions to you. The preparer reviews the draft, validates each changed figure, and approves. Your firm signs and transmits.
How do I run the amended-return workflow?
The workflow takes six steps, from opening Cowork Tax Prep to approving the draft.
STEP 1 Open the Cowork Tax Prep workflow. In TaxGPT Cowork, go to Workflows and find Cowork Tax Prep under Tax Prep & Compliance.
STEP 2 Select Cowork Tax Prep. The workflow opens a prompt template with fields for the client, form, software and source files.
STEP 3 Fill in the template. Enter the client name and tax year, set the form to 1040-X Amended Return, and describe what changed. Attach the documents or give their folder path, for example /amended_return_test/source_documents/. Name your tax software; if you leave it blank, Cowork confirms it with you before it starts, and it stops if no platform skill is installed for that software.
This example attaches a test packet of source documents (fictitious data) and the original return calculation.
STEP 4 Run the workflow. Cowork sets out its task and scope: it reads the documents, confirms the amendment reason and path, and confirms the tax software before it does anything in it.
STEP 5 Review the output. Cowork returns a summary of the run (path taken, Column A status, the explanation entered, lines changed and any open preparer decisions) with the review workpaper. This example uses Markdown; you can ask for any format, and we recommend a branded PDF or HTML for anything client-facing.
STEP 6 Confirm and approve. Check the review workpaper and the resulting refund or balance due, then approve before your firm files.
What does Cowork produce?
Output | What it contains |
Draft Form 1040-X | Columns A (as originally reported or previously adjusted), B (net change) and C (corrected) for each changed line |
Review work paper | Each change tied to its source document |
Part II explanation of changes | Drafted from your stated reason and entered once you approve the wording |
Rebuilt original return | Path B only: the as-filed return re-entered in your software from the filed copy or transcript |
Column A verification | Confirmed clean, or each mismatch listed by line for you to resolve |
State amendment flag | A note when a state amended return may be required (state returns are not prepared in this workflow) |
Changed forms and schedules | Any forms and schedules that changed, placed behind the updated Form 1040 when filing on paper |
Updated Form 1040/1040-SR/1040-NR | A complete updated Form 1040, 1040-SR, or 1040-NR reflecting the amendment, required when filing Form 1040-X on paper |
What do I need to review before filing?
☐ Each Column B change matches the client's confirmed documents
☐ Column A verification is clean, or each mismatch is resolved
☐ The rebuilt original, if used, matches the filed return or transcript on AGI, taxable income, total tax, payments, and refund or balance due
☐ The Part II explanation is accurate and complete
☐ The refund-claim deadline is confirmed for each year
☐ A state amended return is prepared separately, if one is required
☐ E-file eligibility confirmed, or the return is set up for paper filing
☐ For paper filing, a completed, updated Form 1040/1040-SR/1040-NR is attached, with all changed forms, schedules and supporting documents in the IRS-prescribed order
☐ The final refund or balance due is correct before you sign and transmit
FAQ
What documents does Cowork need to get started?
The corrected or newly received documents behind the amendment, plus the original return: either in your current tax software (Path A) or as a copy of the filed return or an IRS transcript (Path B). Cowork does not rebuild an original from W-2s and 1099s or infer values from incomplete documents. If something is missing, it asks before going further.
Who decides what changed, and who files?
Your firm does. Cowork works in your tax software, verifies Column A, enters the changes you specify and drafts the Part II explanation for your approval; it doesn't decide what to change or how to resolve discrepancies. The reviewing professional owns the final amended position. Cowork does not e-file, e-sign, email the client, print, or overwrite the original return without your explicit go-ahead, and each changed figure traces to its source so it can be checked before delivery.
What if the original was filed outside our current software?
Upload a copy of the filed return or an IRS transcript, along with the original source documents if available. Cowork re-enters the as-filed values in your software as a baseline (not marked for e-file), then checks it against your document on AGI, taxable income, total tax, payments, and refund or balance due. It stops on any mismatch before adding Form 1040-X.
Can it handle multi-year amendments?
Yes, one year at a time. When the same error spans several open years, run a separate session for each year, each with its own 1040-X. The refund-claim window under section 6511 is generally 3 years from filing or 2 years from payment, whichever is later. Cowork flags that deadline for the reviewer to confirm. Electronic filing is generally available only for the current and two prior tax periods, and your tax software must support the amended return. Older amended returns must generally be filed on paper. If the original return for a prior year was filed on paper earlier in the current calendar year, the amendment must also be filed on paper.
Does it handle federal and state amendments together?
Not in this workflow. Cowork prepares the federal 1040-X and flags when a state amended return may be required, so your firm can prepare it separately.
What if a figure can't be sourced?
Cowork does not invent or estimate amounts. Each figure on the 1040-X traces to a source document, a value you provided, or arithmetic on those. If a required value has no source, Cowork asks before going further.