You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: My name is George Lee. Due to some personal issues, I would like to postpone my trip to some other dates. Please help me in changing my existing reservation.

ASSISTANT: Sure, please wait for a minute, let me check.

USER: Sure, take your time.

ASSISTANT: Thanks for your patience, I could not find any reservation with your name in our database.

USER: It's ok, no issues. Thank you for the information.

ASSISTANT: You are welcome.