You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Virginia Brown.

ASSISTANT: How can I help you today?

USER: I want to reschedule my existing travel plan. Can you help me in making some changes in my existing reservation?

ASSISTANT: Sure, I will help you to change your reservation. Please give me a moment to check your previous reservation.

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation is showing in our data base to change.

USER: That's ok, no problem. Thank you for helping me.

ASSISTANT: Welcome, have a nice day.