Having a Bridge(II) by itself doesn't allow you to copy the effect of one of your own occupied districts, because Bridge lets you copy only the effects of a building in another player's district.
If you did have Bridge(II) and your opponent had Bridge(I), you could not copy the effect of one of your occupied buildings because Bridge(I) can't do that. But there is another trick you can do.
You can use your own Bridge (of either type) to copy the effect of an opponent's Bridge (of the other type) to copy the effect of one of your buildings of a different color (i.e., yellow or red). This is because Bridge (unlike Port and Road) is not limited by color.
[If yours is Bridge(I), you can do this only if the opponent's Bridge(II) is unoccupied. If yours is Bridge(II), you can do this only to copy the effect of one of your own unoccupied buildings.]
This trick might be useful if you have only white citizens available. Or maybe because your opponent's is Bridge(I) (limited to available buildings) and you want to use this trick for a yellow building and then later activate the yellow building with a yellow citizen. (If you used the yellow citizen first, the building would be occupied and its effect could not be copied via the opponent's Bridge(I).)