You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you?

USER: Myself Sarah Miller.

ASSISTANT: Glad to meet you Miller.

USER: I would like to change my previous source and destination codes, which is done recently. Can you please help me out?

ASSISTANT: Sure, I am here to help you out.

USER: Thank you for accepting my request.

ASSISTANT: Sarah Miller, we haven't found any reservation under your name in our database.

USER: Not a problem, thank you for your kind information.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your service.