Hi @JO
Welcome to Microsoft Q&A! Thanks for posting the question.
I believe you are using send approval email to send an email to approve or reject the request. The send approve email action returns ApprovalEmailResponse which is of type string having only value as Approve or Reject.
Unfortunately, there is no way to know which user has approved/reject the request. Anyone who has the right URL (if executing in the private browser too) which you receive at your email address can approve/deny the request.
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