Did you claim the Recovery Rebate on your original return?
You cannot amend a return for the Recovery Rebate Credit since their was a Recovery Rebate credit on your original return and the IRS corrected the amount. The IRS will send you a letter regarding the change in your return, and information on what to do if you don't agree.
The following is from the IRS about amending a return for the Stimulus payment:
1) If you didn't claim the credit on your original tax return you will need to file a Form 1040-X, Amended U.S. Individual Income Tax Return, to claim it. The IRS will not calculate the 2021 Recovery Rebate Credit for you if you did not enter any amount on your original tax return, or you entered $0.
(2) DO NOT file an amended tax return if you entered an incorrect amount for the 2021 Recovery Rebate Credit on your tax return. If you entered an amount other than $0 on line 30 but made a mistake in calculating the amount, the IRS will calculate the correct amount of the 2021 Recovery Rebate Credit, make the correction to your tax return, and continue processing your return. If a correction is needed, there may be a delay in processing your return and the IRS will send you a notice explaining any change made.
https://www.irs.gov/newsroom/2021-recovery-rebate-credit-topic-h-correcting-issues-after-the-2021-ta...
