Ok ... if you are talking about the first 2 stimulus payments that were reconciled on the 2020 return then when the IRS recalculates the return that will also be recomputed.
If you are talking about the third stimulus payment when they recompute the original return they are also recalculate the third stimulus and send out a "PLUS UP" payment. https://www.irs.gov/coronavirus/get-my-payment#plusup
