You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you now?

USER: I am trying to change the travel dates in my past reservation, can you please help me to do that?

ASSISTANT: Sure, I will help you with that. Can I have your  good name please to check your  reservation status?

USER: I am happy for you quick response. My name is Christine Thomas.

ASSISTANT: Ok,  please wait a  moment.

USER: Sure, I can wait for your response.

ASSISTANT: Sorry Christine Thomas, no reservation has found under your name to change.

USER: Oh! It is sad to hear from your end. Anyways thank you for your time.

ASSISTANT: Thank you for choosing us, have a good day.

USER: Most welcome.