You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Rebecca Garcia here.

ASSISTANT: Garcia, nice to meet you.

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

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry Garcia, there is no reservation found on your name to change your reservation.

USER: Ok, thank you for the information.

ASSISTANT: You are welcome.