In Josys, you can change the device assignment date for the assignee.
Steps to change the device assignment date
Step 1: Go to the device for which you want to change the device assignment date. Click and select the View All Users option.
Step 2: Click 
and select Edit Assignment Date to modify the date of the device assignment.
Step 3: Select the date from the calendar that you want to keep and click Save.
The device assignment date gets updated.