You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your sweet name please?

USER: My name Jacob Green.

ASSISTANT: Nice to meet you Jacob. How may I assist You today?

USER: I want to change my reservation can you help me?

ASSISTANT: Sure Jacob, please wait for a moment, I will get back with details.

USER: OK.

ASSISTANT: I am really sorry for to tell you, I cannot find any reservation with your name.

USER: OK. Thank you for checking.

ASSISTANT:  It was my pleasure, thank you for contacting us.