How to drop milk supply suddenly

Hello mummies! I suddenly got a job offer and will start work on Monday. My current pumping schedule is 6am, 12pm, 8pm, 12am. I dont think is possible for me to pump on my first day of work. If i drop my pump at 12pm, that will be 14 hrs of not pumping. I afraid i might get mastitis.. anyone mummies pump & dump at toilet during lunch hours??? Help :( how should i go about it..