You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Rachel Thomas.

ASSISTANT: Welcome to flight booking agency Rachel Thomas.

USER: Thanks, I want to change my travel dates in my previous reservation. Can you please help me with that?

ASSISTANT: Sure, I am glad to help you with that.

USER: Thank you.

ASSISTANT: Please wait a moment to check your previous reservation.

USER: Ok.

ASSISTANT: We regret to inform you that there is no reservation found on your name in our database.

USER: Oh! It's ok no problem. Thank you for your information.

ASSISTANT: Thank you for reaching us, have a great day.