You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Charles Mitchell. I want to change an existing reservation, due to some personal issues. Could you help me in changing a reservation?

ASSISTANT: Sure, I will help you. Please share me your new travelling dates?

USER: My departure is 10/30 and return date on 11/01.

ASSISTANT: Do you have any specifications?

USER: I need a direct flight.

ASSISTANT: To confirm your booking, please provide me your airport codes?

USER: My source is Austin TX - AUS and destination is CA - SFO.

ASSISTANT: OK, please wait a while.

USER: Sure.

ASSISTANT: We found a 1007 UA airline with single connection and price of 100. Shall I proceed with booking?

USER: You can proceed to booking.

ASSISTANT: Your ticket has been booked.

USER: Thanks for your service.

ASSISTANT: Thank you for reaching us.