You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Ronald Roberts here.

ASSISTANT: How may I help you?

USER: I have planned a trip with my students to enjoy the holidays in water world but some of the students were effected with health issues, so I would like to change my reservation to another date to go there. Can you please help me out with changing of my reservation?

ASSISTANT: Sure, I will help you in changing your reservation.

USER: Thank you.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, there are no reservations found.

USER: Oh! I think the ticket was not booked due to server issue.

ASSISTANT: Thank you for choosing us.

USER: Anyway, thank you for the information.