You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am very interested in trekking and I have reserve a plane ticket to enjoy in Mountain Valley, but I am unable to travel on that dates due to my annual examinations. Can you please change my existing reservation?

ASSISTANT: Sure, I will help you on that. Could you please provide your name to check your previous reservation status?

USER: I had done the plane ticket on Ruth Martin name.

ASSISTANT: Ok, please hold on a moment to check.

USER: Sure.

ASSISTANT: Sorry Martin, there is no reservation found under your name in our records.

USER: Ok, that's fine. Not an issue with that, anyways thank you for your good job in my help.

ASSISTANT: Thank you for using our services, have a great day.