You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Kevin Parker here, can you be a helping hand,  I want to change my return time in existing reservation?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: There is no reservation found on your name.

USER: No problem, I will think for any other option. Anyway, thank you for checking.

ASSISTANT: Thank you and have a nice day.