You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I want to change my reservation, because I have some another important work on those dates, can you please change my reservation?

ASSISTANT: Sure, may I know your name please to check the reservation status?

USER: Sure, my name is Jonathan Harris.

ASSISTANT: There is no reservation found with your details, Harris.

USER: Oh! may be I am not booked my ticket properly at that time. Thank you for your information.

ASSISTANT: Thank you for choosing us.

USER: Welcome.