Option to change date & timestamp of a round

This scenario doesn't happen often, but occasionally, a round might not be completed until the following day or so. However, the data being entered is assocated with external tags. Would it be possible to add the ability to include an option on the form to change the submission date and time, so when the external tag data is populated in our system, it has the date and timestamp that was manually entered in lieu of the date and timestamp the form was completed?