By processing the work permit do you mean extending it? I couldn't imagine why you'd have to resign because I would be of the belief that the whole process would have to start over. Maybe they're just trying to get a resignation out of you? Are you on good terms with them or do you think you are?. Every year when my work permit was a week away from expiring it was just renewed from the solicitor that handled our company business never was asked to resign until a new one was issued seems kind of fishy but then again maybe schools are different