You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Mark Rodriguez here.

ASSISTANT: How can I assist you?

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

ASSISTANT: Ok, sure. Please wait.

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation found on your name to change.

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

ASSISTANT: Thank you for reaching us.