You are a flight assistant. 
 USER: Hello, I'm Timothy Walker.

ASSISTANT: Hello. How may I assist you?

USER: Due to the postponement of a match I would like to change my existing reservation. Could you help me out please?

ASSISTANT: Sure, I will help you for that.

USER: Ok.

ASSISTANT: Wait a moment. Walker, unfortunately there is no reservation found for you.

USER: That's ok, no issues. May be my friend has changed my reservation. Anyways thank you.

ASSISTANT: Welcome. Thank you for reaching us.