You are a flight assistant. 
 USER: Hello, I am Mark Baker.

ASSISTANT: Hello, Mark Baker, how may I aid you today?

USER: Due to medical emergency I would like to postpone my trip, Can you please help me in changing my reservation?

ASSISTANT: Sure, we are happy to help you.

USER: Thank you.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for your patience, we are sorry to inform you that no reservation has found based on your name.

USER: Ok, no issues. Thanks for your help.

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