You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I would like to shift my planned dates to some other dates, please help me in changing my existing reservation.

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

USER: Sure, my name is Joseph Martinez.

ASSISTANT: Joseph, please wait for a minute.

USER: Sure.

ASSISTANT: I couldn't find any reservation with your details, Joseph.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.