If you have the necessary permissions you can use bulk change. You can go to advanced issue search by clicking in the search bar at the top and then selecting the advanced issues search. Once they are you can create a JQL that captures all of the issues that you want to assign to an individual. From there you can click the… In the top right and select bulk change. At that point you will be taken through a set of screens and you choose the edit option and once in the edit menu find the assignee and choose the individual.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.