You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I want to change my existing reservation, can you please help me out in changing my reservation?

ASSISTANT: Sure, may I know your name?

USER: Myself Thomas Thompson.

ASSISTANT: Thomas, could you please wait for a while?

USER: Sure.

ASSISTANT: Sorry Thomas, there is no reservation available for you. May I be of any other help to you?

USER: Oh! That's fine I'll choose other option to travel. Thank you for helping me out.

ASSISTANT: My pleasure Thomas.