Who can use this feature?
You cannot modify submitted registration forms. However, there are a few solutions if changes are requested.
You can contact the submitter to request they submit a new form, or, if payment was accepted, you may choose to complete another form on their behalf. Administrators can skip payment so that payment information will not run twice.
Additionally, you can add an internal field to the registration form for "Internal Comments". This way, you can make notes on the submission if a user requests a correction or update.