You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Stephen Perez.

ASSISTANT: Stephen Perez, how can I help you?

USER: Can you help me in changing my reservation?

ASSISTANT: Sure, please give me a moment to check your ticket status.

USER: Sure.

ASSISTANT: Sorry, no reservation is available by your name.

USER: That's ok, thank you.

ASSISTANT: Thank you for choosing us.