You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I serve you at this moment?

USER: Could you please help me to update my travelling dates in my existing reservation?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Can I know your good name  to check with your existing reservation status?

USER: I made a reservation by this name Nancy Phillips.

ASSISTANT: OK,please wait for some time.

USER: Sure.

ASSISTANT: There is no existing reservation found on your name in our data base.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.