You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I want to modify my reservation details, can you help me out please?

ASSISTANT: Can you provide me your name to check the reservation records?

USER: Myself Andrew Johnson.

ASSISTANT: Sorry Johnson, according to our records there is no reservation done on your name.

USER: That's ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing our agency.

USER: Welcome.