Change state entities ticket

I have no problem in changing the state entity and ticket.
When you can change the status of a ticket?
when it is open, closed?
to change the status of a ticket closed, you have to reopen it?
How it works?
it is possible to have an explanation of what kind of operations you can do when a ticket is opened or closed?

Hello @spanky. We have some information about state feature here:

You can not change state when the ticket is closed?

No you can’t change state if ticket is closed. You should keep it open if you still need to change state.

Mark Ticket as Closed action closes ticket so you can modify it’s behavior to fit into your workflow.

Also Open Closed Ticket action from Advanced Ticket Actions module may help.