...
To do reset the timer for an individual student:
(June-July 2020 : make sure you're on our back up server where this functionality lives: https://lbtest.cns.utexas.edu/instructor There will be code push late July/early August to make this the new standard)
navigate to the specific assignment, answer key (on the left side bar that is revealed after clicking the three horizontal lines at the top), select specific student, and click 'reset timer'
...