Quote Originally Posted by dbbyleo
Ummm...I may wrong on this, but once a segment is in a LMT, you can't control any of it's extent sizes. When you specify the EXTENT MANAGEMENT LOCAL clause, the default is AUTOALLOCATE (the other option is UNIFORM). But once AUTOALLOCATE or UNIFORM is specified, user has no more control over extents sizing.

This is how I've understood this to be. So I don't understand what you're talking about...
But databases normally have more than one tablespace. So you can create different tablespaces with different extent sizes, so if you want to change an extent size, than move it to a different tablespace. I don't understand your confusion.