You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I serve you today?

USER: I am Helen Harris. I would like to change my existing reservation, due to heavy rainfall my golf event has been preponed. Can you please help me with reservation?

ASSISTANT: Sure, I am happy to help you. Please wait for a while, I will check and get back to you.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your given name.

USER: No issues.

ASSISTANT: Thanks for choosing us.

USER: Thank you.