Lightning lane modifications

[ceejanerun]

We are a party of 9 attending HS later this week. When booking LLs, 2 of the 9 requested I book Millenium Falcon while 7 wanted Slinky Dog. SD is booked for first thing in the morning, MFR is booked later in the day. After scanning into SD, can we modify the MFR to add the other 7? We had a similar situation yesterday at Epcot - 2 people held LLs for Remys , and after riding the first ride, we were trying search for Remys for the other 7, but it wasn’t coming up as an option. It was showing as already chosen, even though it was only for 2 people. So last night I wondered, perhaps I should have attempted to modify the existing reservation to add everyone else, once eligible to make another selection.