You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I need to change my existing reservation as my plan to visit my grand parents home got postponed. Can you help me in doing that?

ASSISTANT: Sure, I will help you in changing the reservation. May I know your name please?

USER: I am Karen Robinson.

ASSISTANT: Sorry, there are no reservations found in our database.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you for the information.