You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I address you?

USER: I want to change my existing reservation due to sudden postpone of my football match. Can you help me with that?

ASSISTANT: Sure, will you please let me know your name?

USER: I am Mark Mitchell.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: We found a reservation on your name. Can you please forward your dates?

USER: My trip dates are Dec 26 and Dec 28.

ASSISTANT: Ok, may I know your take off and landing airport codes?

USER: My source is DCA and destination is BOS.

ASSISTANT: Do you have any specifications?

USER: I need a direct flight.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Thanks for waiting, there are no flights going on your way at this moment.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for opting us.