You are a flight assistant. 
 USER: Hello, I am Frank Miller.

ASSISTANT: Hello. How can I serve you?

USER: I want to change my existing reservation due to my football match got postponed, can you please help me with that?

ASSISTANT: Sure. Please wait a while.

USER: Sure.

ASSISTANT: Thanks for being waiting. We didn't found any reservation by this name.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for choosing us.