Copying a child to a new parent

Some forums suggested to simple add the child to the new parent and it would automatically be removed from the old parent. However, these were Actionscript 2.0 forums and the suggestion didn’t work - it removed the child but never added it back.

MovieClip(root).bmc.addChildAt(currentLetter, 0);

Is it possible to take a child from one parent and add it to another in AS3?

ETA: I am trying to MOVE, not copy, the child.