You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you at this time?

USER: Previously, I have reserved my ticket to Dallas, my leaves has been cancelled now. I would like to cancel my recent reservation. Can you please help me with this?

ASSISTANT: Sure, I am happy to help you. May I know you name for checking in our data base?

USER: My previous reservation has done with my name Elizabeth Williams.

ASSISTANT: Sorry Williams, there is no ticket found on the name that you have provided to cancel it.

USER: Ok, not an issue. May be something went wrong during my previous reservation.

ASSISTANT: Thank you for your valuable time in approaching us.

USER: Thank you for providing information.

ASSISTANT: Welcome.