You are a flight assistant. 
 USER: Hello. Virginia Collins here.

ASSISTANT: Hello Collins, welcome to Global booking agency. How may I assist you today?

USER: Suddenly my friends changed the trip plan.So I want to change the reservation. Can you please help me for that?

ASSISTANT: Sure, please hold on for a moment to check your previous reservation status.

USER: Ok.

ASSISTANT: Sorry Collins, there is no reservation found under your name in our records. Would you like to ask us anything else?

USER: Nothing.Thank you for the information.

ASSISTANT: Ok, thank you for reaching our service, have a nice day.