Fast Pass Time Expired

[jans2kids]

What happens with the new Fast Pass + system if you miss your window and don't use the fast pass and didn't pick a new time before it expired? Can you choose a new time and/or ride if available? I know you can choose a 4th now but do you have to actually use all 3 first? What if its my 2nd of the day in the morning and my 3rd isn't until later in the day can I still replace the 2nd one?

[DisneyDadfromPittsburgh]

We just returned from WDW yesterday after being there for four days. What happened to us was on Saturday when we were in Hollywood Studios in the morning we rode everything we wanted to and did not need to use our FP+ choices.
So we had to either wait until the time pasted when they were valid to be considered used or go to customer relations to have them cancelled in order to pick up new ones in Epcot later in the afternoon.
There are FP+ Kiosks all around the parks but they are only to pick a new FP, if you want to change or cancel any you either have to do it on your phone or go to customer relations.
For now, you can not get your 4th until the original 3 are all used or expired.
And no surprise, once we got over to Epcot in the afternoon, all FPs for Soarin and Test Track were gone for the day.