Process for switching to spouse’s new plan during SEP

I’ve done a bunch of searching and can’t seem to find an answer to our situation. Wife and I are both currently on my employer’s PPO plan. She just started a new job and is in the SEP period for her employer’s health plan. Her employer offers a very nice HDHP with HSA. After crunching the numbers, it makes sense for both of us to join her plan and completely drop mine.

This is where my confusion starts. Her employer told her that during this SEP, we can both join her new plan and that they would provide me with a form to give to my employer to completely drop my insurance. Is this accurate? I’ve been trying to verify the process, but have not been able to find anything. Also, as a follow-up, I have an FSA through my current plan. I assume that if I am able to drop my plan during this SEP, I need to spend the FSA before the process is completed. Is that also correct?

I will be speaking to my employer as well. They can be somewhat difficult to deal with at times (private company), so I wanted to ask here first and have as much information as possible.