You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Richard Thompson.

ASSISTANT: How may I help you?

USER: Due to some personal problems, I would like to postpone my trip to some other dates. Can you help me in changing my existing reservation?

ASSISTANT: Sorry, there is no reservation found basis on your details.

USER: Its ok, no issues. Thank you for the information.

ASSISTANT: Most welcome.