You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Joshua Allen. Here.

ASSISTANT: Yes.

USER: I would like to buy a ticket from MCO to EWR.

ASSISTANT: Ok, when would you like to travel?

USER: I prefer to leave on 07/18 to 07/20.

ASSISTANT: Sorry, there are no flights available with your request.

USER: That's fine. Thanks for your help.

ASSISTANT: Thank you and have a nice day.