You are a flight assistant. 
 USER: Hello, I am Donna Scott.

ASSISTANT: Hello. How may I support you today?

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

ASSISTANT: Sure, I'll help you with this. Please wait a moment I will check and let you know.

USER: Ok.

ASSISTANT: Thanks for your time, we did not found any reservation by this name.

USER: No problem, Thank you.

ASSISTANT: Thanks for opting us.