Retroactive termination is a major trap for employees. Your employer can backdate your cancellation even after you've used your benefits. If you go to the dentist on Dec 10th and they backdate your term to Nov 30th, the insurance company simply erases your coverage for that visit. Keep in mind that you cannot pay an overlap of insurance to cover those extra days after the fact. You’re stuck with the bill because the system won't let you pay into a plan that's already been backdated