You will send the Form 1040X Amended Tax Return and that's probably all you need to send. If you removed dependents, that will be fine and the IRS shouldn't ask for anything else. If you added dependents, and they were claimed by someone else, you may need to prove they qualify for you to take them. The IRS will let you know what, if anything, you need to send.
Amended returns have
to be printed and filed by mail. It can take the IRS up to 12 weeks or
longer to process them. If you are due a larger refund than on your
original return, your amended return should only show the difference and you
will receive a separate check for it. If you owe money on your amended
return, it will show only the new amount owed, you will have to mail a check
with the return.
How to Amend?
https://ttlc.intuit.com/replies/3288565
