You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you for today?

USER: Frank Thomas this side.

ASSISTANT: Frank Thomas, what can I do for you?

USER: Please help me in making some changes in existing reservation, due to my busy schedule on my previously planned dates.

ASSISTANT: Let me search for your existing reservation.

USER: Ok.

ASSISTANT: I couldn't find any reservation by your name Frank Thomas.

USER: It's ok.

ASSISTANT: Thank you for choosing our agency.

USER: Most welcome.

ASSISTANT: Have a great afternoon.