Here's pause and adjust an employee's vesting schedule when they go on a leave of absence.
Stop Vesting
You can stop a security's vesting during a leave of absence.
In the Plans & Equity Awards tab, select the grant. Then, select "Exercise & Termination":

Stop vesting for employee as of stop vesting date:

When the employee returns, you can select "Restart Vesting". Vesting will be resumed from the when it was stopped.
