You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Benjamin Roberts here.

ASSISTANT: Roberts, how may I help you today?

USER: My exams dates have been postponed. So, I want to change my reservation. Can you help me?

ASSISTANT: Sure, I can help you to change your reservation. Please give me a moment to check your existing ticket details in our database.

USER: Sure.

ASSISTANT: Sorry Roberts, we could not find a reservation by your name.

USER: It's fine. Anyway, thank you for your help.

ASSISTANT: Thank you for contacting us.