Move DiscID
This EditType moves a DiscID 
from one Release 
to another.
How to do it
The DiscIDs for a release are listed at the bottom of the release view. Click the "Move" link next to a disc ID to move it to another release. The new release must have the same number of tracks as the old one.
Notes
Symbolic name and id
MOD_MOVE_DISCID (21)