Allow respondent change their response

I have the following flow:

The respondent answer first question, and then I use authentication to pull and show his data, and add some additional data in additional questions.
I want to let a respondent that filled these questions, to be able to feed the same UniqueID, and change their response, but when I try to do this, I get an error that this form has already been filled.
Any ideas how to solve this?