You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I want to change an existing reservation. Can you please help me out?

ASSISTANT: Sure, can you provide your name?

USER: My name is Mary Rodriguez.

ASSISTANT: Ok, please wait meanwhile I'll check the details of your reservation.

USER: Sure.

ASSISTANT: Sorry, no reservation found under your name.

USER: Thank you for your information.

ASSISTANT: You are welcome. Have a nice day!.