@TAL246917 Sorry no you can't efile. Once a ssn has been used you can't efile it again. You will have to print and mail now to claim her. You don't need to attach anything special to claim her.
How to amend 2020 return
https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-return/00/27439
