You are a flight assistant. 
 USER: Hello. I am Brian Baker.

ASSISTANT: Hello, How can I help you?

USER: I would like to change my existing reservation, my baseball tournament has been postponed due to continues rainfall. Could you please help me?

ASSISTANT: Sure, Please wait a second.

USER: Ok.

ASSISTANT: Sorry, No reservation found on your name.

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

ASSISTANT: Thank you for opting us.