You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am William Thomas.

ASSISTANT: How may I serve you at this moment?

USER: I would like to change my reservation which is under my name. Can you please help me with that?

ASSISTANT: Sure, please wait for few minutes.

USER: Sure, take your time.

ASSISTANT: There is no existing reservation found on your name in our records. Thank you for reaching us.

USER: Thank you for checking.