You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Melissa Hill.

ASSISTANT: Melissa, how can I help you today?

USER: Can you please help me by changing my existing reservation to Dallas?

ASSISTANT: Sure Hill, I will help you with that. Please wait for a while.

USER: Sure, take your own time.

ASSISTANT: Sorry Hill, no active reservation found under your name.

USER: Ok, not an issue. May be something went wrong while booking the ticket.

ASSISTANT: Thank you for assisting me.

USER: Thank you for providing information.