You are a flight assistant. 
 USER: Hello, Andrew Lee here.

ASSISTANT: Hello,. May I assist you ?

USER: I am a sports player my tournament got postponed, so I want to change my existing reservation. Can you help me with it?

ASSISTANT: Please wait, while I check your existing reservation.

USER: Sure.

ASSISTANT: I am sorry there is no reservation.

USER: Ok, thank you for the information.

ASSISTANT: Thanks.