You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Justin Thomas.

ASSISTANT: How can I help you at this moment?

USER: I want to change my existing reservation due to postpone of my exams, can you help me with that?

ASSISTANT: Sure, I will help you with this. Please give me a moment to check your reservation status.

USER: Thank you. Sure.

ASSISTANT: Justin Thomas, there is no active reservation found under your name in our database.

USER: No issues, thank you for the information.

ASSISTANT: Thank you for opting us.