How to Correct a Form 7004
Quick answer
Before the due date, send a new, complete Form 7004 with the right information. The IRS matches an amended application to your original request. After the return's original due date, a new Form 7004 can't fix it: file the return as soon as you can.

Wrong form code
The extension applies only to the return named on line 1. If you used the wrong code, file a separate Form 7004 with the right code by that return's original due date. All 34 form codes.
Wrong name or EIN
If the name doesn't match IRS records or the identifying number is wrong, the instructions say you won't have a valid extension. Send a corrected Form 7004 before the due date, with the name exactly as it appears on last year's return and the right EIN.
Wrong tax year or amounts
Send a corrected, complete Form 7004 before the due date. The IRS manual says an amended application is researched and matched to the original request. Don't send an identical copy of the form you already mailed: the IRS treats a copy with the same EIN, name, form type and tax period as a duplicate.
Your address changed
A new address on Form 7004 doesn't update IRS records. File Form 8822-B to change a business address.
Your e-filed Form 7004 was rejected
Fix the problem and resend it, or file on paper. A paper Form 7004 still counts as on time if you file it by the due date or within 5 calendar days after the rejection notice, whichever is later. Fixing a rejection.
The IRS denied it
Follow the letter's instructions. If the IRS says your Form 7004 was late but you mailed it on time, send proof of the mailing date, such as your Certified Mail receipt. The IRS manual says a request denied as late is approved if the taxpayer shows it was postmarked on time.
The due date has passed
There's no late extension, so a new Form 7004 won't help. File the return as soon as you can and pay what you owe. What late filing costs.
You need more time than the extension gives
The automatic extension is the maximum for most returns. The IRS manual says a second request for more time is denied once the maximum extension has been granted.
Fill out Form 7004 free. No account needed.