You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I serve you today?

USER: Joshua Campbell here, due to sudden changes my exams has been postponed. I want to alter my reservation. Can you please help me with it?

ASSISTANT: Sure. Please, wait for a while.

USER: Ok.

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

USER: Not an issue, thank you.

ASSISTANT: Thank you for choosing us.