What happens if I teleport to another state using 2000 diamonds with a lvl 12 homebase?

Teleporting to another state (using an advanced teleport for 2000 diamonds) will just put you there as a visitor / invader. Depending on the events you are experiencing in your state this might be for a doomsday attack or conquest of plots. Or on the weekend you may be there to attack bases for a clash of zone kill event. You will not have changed state though and will need to return to your own state.