Suppose my opponent is tapped out while playing Sliver Overlord as his commander, which has the ability:
{3}: Gain control of target Sliver. (This effect lasts indefinitely.)
On my turn, I play a Rite of Replication, targeting his Sliver Overlord. I now have a copy of it in play.
May I then use the {3} ability to steal his Overlord, and then due to the Legendary rule, sacrifice the copy and retain control of his commander?