Hello @HeatherT383 ,
If you have advanced permissions turned on in your Settings, for mass-changing permissions I'd recommend uploading a CSV / XLS file with all those email addresses that need changing. On the page where you mark that you understand permissions and select a permission type, select the one you want and continue to uploading. You can just upload this file to a separate list (won't affect their other list memberships), and then Delete the List Only.
Additionally, once advanced permissions are turned on, you can mass unsubscribe people by uploading a file of email addresses.
Have you tried deleting the contacts out of the system (exporting and downloading them first), then reuploaded them to applicable lists, @HeatherT383? Beyond that, you may need to speak with our Review team to see if they have any additional insight to get these contacts switched to express permission en masse.