Slightly OT, but be aware that in booking an Uber ride in advance will probably cost you more, and there is no guarantee that an Uber will show up at the time you booked. Basically the system doesn't pre-assign anything, but just adds your ride to the system automatically when it's almost time (not any different from if you would just use the app at that point in time).

E.g. https://www.reddit.com/r/uber/commen..._uber_reserve/