You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Jerry Jones.

ASSISTANT: How may I assist you today?

USER: My sister's marriage got postponed, I would like to change my existing reservation. Please help me out.

ASSISTANT: Jerry Jones, please wait for a moment till I check with your existing reservation.

USER: Sure, take your time.

ASSISTANT: Sorry, there is no reservation was found under your name. Thank you for consulting with our services.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Have a nice day ahead.