1. You find new employer.
2. New employer requests LMO from Service Canada, has to have advertised the position and no canadians/Pr qualified.
3. If employer gets the LMO, you send the the LMO and IMM 1249 with fees to Vegreville for new work permit.
4. You cannot start work for new employer without a new work permit.
5. If you don't require a medical, you could apply at the Border point with the LMO. No guarantees though that it will be issued.