You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Michael Lee from Charlotte.

ASSISTANT: How may I help you today?

USER: I want to change my travel dates in my previous reservation, due to some problems I am unable to travel those dates so can you help me with that?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry to inform you, there is no reservation found with your name in our database.

USER: Oh! It's ok no problem. Thank you for your service.

ASSISTANT: You are welcome. Thank you for reaching us.