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

ASSISTANT: Hello, how may I help you today?

USER: I want to alter my reservation. can you please help me with it?

ASSISTANT: Sure. 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.