You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I want to do some changes in the existing reservation because my friends are not able to come on the those dates, can you please help me?

ASSISTANT: Give me a moment.

USER: Sure.

ASSISTANT: Sorry, I didn't found any reservation basis on your details.

USER: It's ok.

ASSISTANT: Can I know your name for further proceedings?

USER: My name  is Joshua Perez.

ASSISTANT: Thank you for reaching us.

USER: Thank you for your time.

ASSISTANT: Most welcome.