You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I abet you today?

USER: Stephen Lewis here. Could you change my reservation?

ASSISTANT: Sure, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry, there are no active reservations on your given name to change.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching our service.