You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Anna Harris.

ASSISTANT: How can I assist you today?

USER: Due to postponing of my seminar, I want to change my recent reservation.Will you help me with that?

ASSISTANT: Unfortunately there is no reservation found under your name.

USER: That's ok, thank you for the information.

ASSISTANT: Welcome, have a great day.