As the DB is in no recovery or standby mode you wont be able to alter the file locations without dropping the database.

The only way would be to drop the database, restore it to the new locations with norecovery, restore all the logs up to the latest log and then let it all just carry on.

Don't need to make any changed to the log shipping plan, let the backups, and copy jobs run as normal, may want to disable the restore job until you have finished then re-enable it again.