You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Jessica Phillips here.

ASSISTANT: Glad to meet you Jessica.

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

ASSISTANT: Sure, I will help you with it. There are no previous reservation with your details. Is there any airport codes and travelling dates?

USER: Nothing, thank you for the information.

ASSISTANT: You are welcome.