You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I guide you now?

USER: Due to sudden work, I want to change my reservation.  Can you please help me with it?

ASSISTANT: Sure, I can assist you and on whose name your flight ticket booking is done previously?

USER: Daniel White here.

ASSISTANT: Wait for a moment.

USER: Ok.

ASSISTANT: Thank you for your patience, I am unable to search your previous booking in our data base to change your booking.

USER: Ok, not an issue. Thank you.

ASSISTANT: Your are most welcome and thank you for approaching us.