You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Dorothy Evans.

ASSISTANT: How may I assist you today?

USER: Can you make changes in my existing reservation?

ASSISTANT: I have checked in reservation list to change your ticket, I could not find any reservation with your name.

USER: It's ok, thanks for checking my status.

ASSISTANT: It's my pleasure, have a nice day.