You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may  I provide assistance to you?

USER: I am planning to change my destination airport code in my existing reservation, can you please help me out?

ASSISTANT: Sure, we are here to help you.

USER: Thanks.

ASSISTANT: May I know on which name the ticket has been reserved?

USER: Sure, my name is Ryan Anderson.

ASSISTANT: Ok, please wait for a while.

USER: Ok, take your time.

ASSISTANT: Sorry, we could not find any reservation with your name.

USER: It's ok, thank you for the information.

ASSISTANT: Thank you for choosing us.