You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid 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: Sure, I will help you with that. Can I have your name please for checking your details?

USER: I am Michael Brown.

ASSISTANT: Michael, please give me a while, I will review your details and revert back to you.

USER: Sure.

ASSISTANT: Thank you for waiting. Sorry, I did not found any reservation showing active in our database for updating your reservation, once please look if it might have cancelled previously.

USER:  It's alright, no problem. I think the ticket is not reserve properly while I am booking. Thank you for your quick help.

ASSISTANT: You are welcome. Thank you for reaching Global Booking Agency.