You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Samuel Thompson.

ASSISTANT: How may I help you out?

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

ASSISTANT: Sure, I will help you in changing the ticket.

USER: Thank you.

ASSISTANT: Sorry, there are no reservations found in our database.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for reaching us.