You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I would like to change my destination airport code, please help me in changing my existing reservation.

ASSISTANT: Can you please wait for a while till I check with your previous booking? May I know your good name please?

USER: My name is Dennis Taylor.

ASSISTANT: Ok, please be on hold.

USER: Sure, take your time.

ASSISTANT: Sorry to inform you Dennis, there is no reservation found by your name.

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

ASSISTANT: Thank you for reaching our services. Have a great day ahead.