You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I would like to change the travel dates in my previous reservation, can you please help me to do that?

ASSISTANT: Sure, I will help you in changing the reservation. May I know your name please?

USER: Thank you. My name is Dorothy Adams.

ASSISTANT: Sorry, there are no reservations found.

USER: It's ok, anyways thank you for checking.

ASSISTANT: Thank you for reaching us.