Mass Reassign Tasks from a User Role to a Specific User

My team and I have recently spent a large amount of time building out our project lifecycle within a Blueprint in Wrike and when creating a project from the Blueprint we would like to be able to update the assignee from a generic User Role to a specific user. Since our teams are always different and can change I'm hoping there's a way to mass edit all tasks within one project assigned to a user/user role to a specific user? I know there is the option to mass edit within the list view but that requires me to go through each task and select which tasks I'd like to change. I'm hoping there is a way to specifically change all tasks assigned to "Project Manager" to "John Smith" at the beginning of a project or if John Smith were to leave I could automatically assign to "Sam Johnson" without having to scroll through the ~300 tasks in a project plan. 

I also noticed that when I am in the mass edit section the checkbox takes the place of the user's initials that are assigned to that specific task which makes the manual updates more difficult. Any help would be appreciated!