You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Ronald Mitchell here.

ASSISTANT: Nice to meet you Ronald. How can I assist you today?

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 changing the reservation as per your request.

USER: Thank you.

ASSISTANT: Please give me a moment, I will inform you the details.

USER: Ok.

ASSISTANT: Thank you for your patience.

USER: My pleasure.

ASSISTANT: Sorry Ronald, there is no reservation has found under your name to change it.

USER: Ok, not an issue. Thank you for your time.

ASSISTANT: You are welcome, have a good day. Thank you for choosing us.