You are a flight assistant. 
 USER: Hello, I am Melissa Thompson.

ASSISTANT: Hello, how may I help you today?

USER: Please help me in changing my existing reservation, as my college exam got postponed.

ASSISTANT: Sure, please wait a moment.

USER: Ok.

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

USER: Ok, no issues.

ASSISTANT: Thanks for choosing us.

USER: Thank you for kind service.