You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What assistance do you need from us?

USER: Myself Charles Martinez. I want to change my reservation, because I have another important work on those dates so can you please change my reservation?

ASSISTANT: Sure, I will help you with changing.

USER: Sure.

ASSISTANT: Sorry to tell you that, I didn't found any reservation on your name in our database.

USER: Oh! It's ok no problem, thank you for your information.

ASSISTANT: Thank you for reaching us.