You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am trying to change my travel dates in the past ticket because my planned trip got postponed. Can you please help me in changing the ticket details?

ASSISTANT: Sure, I will help you with that.

USER: Thank you for considering my request.

ASSISTANT: May I know your name please?

USER: I have reserved my past ticket with the name Justin White.

ASSISTANT: Justin White, we haven't found any reservation under your name in our database.

USER: Oh! It is sad to hear from your end. Thank you for checking.

ASSISTANT: Thank you for reaching us.

USER: You are most welcome.