You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, do you need any help from us?

USER: I need to do some changes in my previous reservation so please help me with changing my reservation.

ASSISTANT: Ok, I will help you with that.

USER: Thank you.

ASSISTANT: Could I have  your name please?

USER: Sure, please check my reservation with the name Anthony Collins.

ASSISTANT: Ok, please allow me a moment.

USER: Sure, take your time to check.

ASSISTANT: Sorry, there is no reservation with your name in our portal to make changes.

USER: I will check my mail once more to get the information regarding confirmation of my ticket. Anyway, thank you for your time.

ASSISTANT: You are welcome, have a great day.