Allow returned submissions to retake experiment


I am a Prolific newbie and I just finished running a small batch of subjects in a two part study. One participant completed part 1 of my experiment successfully but then “returned” their submission for Part 2. This participant later messaged me saying that they had some technical difficulties with their laptop and would like to complete Part 2 of the experiment. How would one go about doing this in the Prolific system? It seems like my only options for their returned submission are to pay them or message them.