Checking my last day of health coverage - what worked for you?

HR said my health plan continues for a bit and I do not understand how. I have read a lot of threads here and could not find my exact situation. I do not want to be surprised by a bill. What should I do about appointments?

I moved my appointments earlier while coverage was active. It saved me a bill.

Ask HR to confirm the exact date in writing. I also called the insurance company to double-check.