You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Joshua Evans. I would like to change my existing reservation, can you please help me?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure, take your own time.

ASSISTANT: Thank you for waiting, There was no reservation found on your given name.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for choosing us.