You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER:  I am John Thompson want to change my reservation owing an emergence in office. Can you help me in changing?

ASSISTANT: Sure, please wait for a while.

USER: OK.

ASSISTANT: Sorry, no reservation found on your given name.

USER: Ok, no issues.

ASSISTANT: Thank you for choosing us.

USER:  Thank you for your help.