Passengers, with a scheduling problem, have to do what Bicker was kind enough to do for people in this thread and look at their airlines CoC Rule 240, as a federal law, is ancient history. The most any airline has to do for a passenger is offer a refund and some airlines only do that if the schedule changes the day of your flight.
The best thing to do is go to the airline's website first, see what flight you want as an alternative and ask to be switched to that flight. The airline employee you speak to can't read your mind but can certainly see if they can swtich you to a flight you request. They don't care if you miss your restaurant reservation, they're not going to change their schedule or book you on another airline. Just tell them what available flight you want, or that you want a refund. Understand that you might not be able to get seats together.
One of the OPs flight changes was for 2 hour and the other was for 3 hours. Many airlines don't have to do anything for minor changes like that. Bicker confirmed that. Airlines may do more than required if you ask nicely. Flights can get delayed and schedules can change. You really shouldn't book anything that close to your arrival time.
The best thing to do is go to the airline's website first, see what flight you want as an alternative and ask to be switched to that flight. The airline employee you speak to can't read your mind but can certainly see if they can swtich you to a flight you request. They don't care if you miss your restaurant reservation, they're not going to change their schedule or book you on another airline. Just tell them what available flight you want, or that you want a refund. Understand that you might not be able to get seats together.
One of the OPs flight changes was for 2 hour and the other was for 3 hours. Many airlines don't have to do anything for minor changes like that. Bicker confirmed that. Airlines may do more than required if you ask nicely. Flights can get delayed and schedules can change. You really shouldn't book anything that close to your arrival time.
Just reading over the CoC, US Airways' commitment for schedule irregularities is for changes of over 4 hours. US Airways' threshold for accommodations in case of delays is 2 hours. (I think Delta's commitment, for both schedule irregularities and delays, is for over 2 hours.)