You are a flight assistant. 
 USER: Hello. Lisa Adams here.

ASSISTANT: Hello Lisa, welcome to ABC agency. How may I assist you?

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

ASSISTANT: Sure, wait a moment to check your previous reservation and I will get back to you.

USER: Ok.

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

USER: Nothing.Thank you for helping me.

ASSISTANT: Ok, thank you for the information, have a great day.