Search for "assignee = <person who has left> and issue is open" (Generally, you probably don't want to reassign ended issues, it's better for your historical view to leave the gone person on closed stuff).
Once you have the list, use "bulk edit" from the issue navigator's option menu, and you'll be able to mass-update the assignee
Hello Community! Quick disclaimer: We are running a contest on Community (The Atlympics!) from July 23rd - August 8th of 2021. If you are interested in participating in this contest (prizes! ...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events