Gaming is for having fun. Fun requires clear rules.
Can you "rearrange" when taking an upgrade action?
In other words, rather than discarding a certain tile, could I move it to a different ship's blueprint? Or, is the rule that once a tile is placed on a blueprint, it can never be moved.....only discarded?
You still can discard and take again this part to other spot.
But it is one of two tiles you can take.
And you can't do this with parts from discoveries.