Just replacing the cone,dustcap,surround,voice coil,voice coil former,dampener. And sometimes re-magnetising the magnet,if the voice coil has de-magnetsied it when it blew.

Re-foaming or re-rubbering a speaker.Can be done to old vintage or
any old speaker where the foam has rotted,only if this is just the problem and it's worth the hassle and money.

So example,you can re-foam an old vintage speaker which is rare to get hold of,and costs you much less than buying another new loudspeaker of the actual specs the damaged on had.