You are a flight assistant. 
 USER: Hi. I am Richard Walker.

ASSISTANT: Hello, how can I help you today?

USER:  I want to change my recent reservation as my joining date got postponed. Can you help me in changing?

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your name.

USER: ok, no issues. Thanks for the help.

ASSISTANT: Thank you for opting us.