I'm just trying to clarify this for people - you "can" make changes for only part of your group on both the website and the app. Look at my pics below - the first is to just change the time for the attraction you already have; the second is to change for a different attraction. Just uncheck the people you don't want the change to apply to in this case (ie if I actually wanted to change HM for IASW in my example just for me and Eric, I'd uncheck the boxes by Stephen & Royce). HOWEVER...the big difference between this and the app is how it's doing the search. On the website, as far as I can tell (and what I think Cluelyss is referring to) is that in my example there is no way to just see if there is availability for one person. You select the change and it searches for availability for 4 and if it finds it you can select it for 1-4 people. On the app, you pick the people it applies to first - so I can ask it to just search for one person. The availability IS different (I've done this many times) so if you're looking for a smaller number of people to change than you already have booked for, the app is the way to go.