I've got the same package and have tried working out numerous scenarios....none of which work....I verified they wouldn't work with WDW **and** with my
travel agent just in case one or the other just didn't want to fool with it.
When booking I tried to work out moving from one resort to another. It didn't work because the VISA package was a four day package. You could book one resort for 4 days and then book the next for four days with two separate ressies, but you'd be paying UPH twice for the day in the middle.....or you could make 3 ressies....4 days UPH good until midnight...room only for move day....recheck in for 4 days next AM to get your UPH....however, we weren't going to be able to go for 9 days. It looks like WDW could look and see the whole stay would be longer than 4 days and be able to work it out...but it doesn't work that way.
The reason you can't change your ressies now is because none of the hotels are offering the VISA package any more and have no more rooms to book for that package. I know...I know...they have the 45 day change thing...but I've found out **not** if you've booked a special package like the VISA deal. You can only make changes during the original time frame because that's when the rooms are available for that deal. Once the time frame is up, the deal's off the table and you cannot change.
Which means if you really want to split your stay, you have to give up the VISA deal and use the discounted room rates....but you end up losing in the end....or at least we would because we'd be having to pay for two of our children and now they're free. Tickets cost more than what I would save in discounted room rates.
If you find out something diff, please let me know.