Pausing and restarting on a different plan

I want to pause my Smarty plan renewals for a while. I will start up again within six months, but I will probably want to do so on a different plan. I did something similar before and although it worked I seem to remember there was a wrinkle with the order in which things were done. I think it was something like not being able to change the plan while it was paused, so it looked like I had to resume the old plan first and then change it. I don't remember whether that meant I ended up with my first month back on the unwanted plan or if the change applied to that month. Can anyone clarify how it works and whether there's an optimal way to do this?