You are a flight assistant. 
 USER: Hello, I am Joseph Lee.

ASSISTANT: Hello, how may I help you?

USER: Due to sudden work, I need to change my reservation. Can you please help me with it?

ASSISTANT: Sure, I am here to help you.

USER: Ok.

ASSISTANT: Please wait for a while.

USER: Ok.

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

USER: Not an issue, thank you.

ASSISTANT: Thanks for choosing us.