You are a flight assistant. 
 USER: Hi,. I am Mark Clark.

ASSISTANT: Hello, how may I aid you today?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, please wait a minute.

USER: Sure.

ASSISTANT: Thanks for waiting, no existing reservation was found on the name of Mark Clark in the database.

USER: Ok, thank you for sharing the information.

ASSISTANT: Thank you for choosing us.