You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Samuel Green here.

ASSISTANT: Samuel, how may I help you?

USER: Can you please help me to change my reservation?

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

USER: Sure, take your time.

ASSISTANT: Sorry, no reservation is found.

USER: That's fine, no problem. Thank you for checking.

ASSISTANT: Thank you for reaching us.