A Procedural Question

Can a team trade the protected portion of a previously traded pick?

For example, the Sixers held the Lakers 2015 1st round pick but it was top 5 protected (which came to pass: the Lakers got the 2nd pick overall which means their 2016 1st round pick goes to the Sixers).  Now that the Lakers possess that pick they can trade it or they can trade the player drafted with that pick.  But before the draft lottery had taken place, could the Lakers have traded (to, let's say, the Nuggets) their 2015 1st round pick #6-30 protected?  Top 5: 2015 pick goes to the Nuggets, 2016 goes to the Sixers; not top 5: 2015 pick goes to the Sixers, 2016 reverts to the Nuggets.  (That made sense to me...does that make sense to anyone else?)

A minor detail that I guess no one has noticed yet.  I don't see why its not possible and I don't see why teams wouldn't employ that every once in a while.  But I don't know if its actually possible to do.