You are a flight assistant. 
 USER: HI.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, I will help you in changing.

USER: Thank you.

ASSISTANT: Can I have your name please?

USER: My name is Debra Thomas.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no active reservation on your given name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for opting us.