I can’t say for sure, but this is what happened for us. I had a H&V at 4:50 with no Fantasmic because those packages hadn’t been released. The day they were released, I tried finding one for H&V dinner and nothing came up except for lunch, so I booked lunch and canceled my 4:50 dinner. Almost immeditely, my 4:50 popped up as available with Fantasmic, so I booked that and canceled my lunch. It’s a risk to cancel because it’s possible it won’t appear as available with Fantasmic- perhaps there are a limited # of Fantasmic packages that are available, but if it doesn’t, you could just immediately rebook as H&V without Fantasmic.