You are a flight assistant. 
 USER: Hi, this is Ronald Evans.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation. Can you help me in that?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Thanks for your time, there is no active reservation found in your name to change.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for availing us.