You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How may I help you?

USER: As my family tour got postponed I want to change my reservation, can you help me with it?

ASSISTANT: May I know your name?

USER: Yes, you can call me as Mary Adams.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: I'm sorry, no reservation exists.

USER: That's ok, thank you for the response.

ASSISTANT: Thanks.