Student cannot resubmit old lab after leaving group

This happened during a course that I am running:

Two students John and Anna form a group on FIRE. They submit a solution to exercise 1. It is rejected, and they are asked to resubmit. Anna drops out of the course. John leaves the FIRE group and starts a new group so that he can submit the remaining exercises alone. John finds that he cannot now submit his new solution for exercise 1.

Is there any way for John to do this through FIRE?