You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Due to sudden change in the dates of summit which was going to be held in the place where I suppose to visit, I want to do some changes in my existing reservation. Can you help in this?

ASSISTANT: Sure, I will help you with that. Please give me a moment. Can you please provide me your good name?

USER: Please, check previous reservation on Amanda Collins.

ASSISTANT: I have tried with your name but no reservation has found under your name.

USER: That's ok. Thank you for your information.

ASSISTANT: Thank you for reaching us. Have a good day.

USER: Welcome.