You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am Charles Robinson. I need to change my recent reservation, could you help me out?

ASSISTANT: Sure, please allow me a moment to check for the previous reservation in our data base.

USER: Ok.

ASSISTANT: I appreciate your patience. Charles, there is no reservation found under your name.

USER: It's fine. Anyway, thank you for your help.

ASSISTANT: You are welcome. Thank you for contacting us.