You mean she filed as independent and not as your dependent?  She will have to amend her return.  You will have to print and mail your return this year to claim her.  Even if she amends it won't clear her ssn.  So you don't have to wait to mail yours.  

How to amend 2020 return

https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-return/00/27439

She will need to file an amendment stating that she can be a dependent of someone else. She may need to pay a portion of her refund back depending on her income.  As for you, you can wait until the IRS completely processes her return before filing yours or you can file now and not claim her dependency and file an amendment later. Even both returns can be efiled, I am not sure how quickly IRS can process this change.