Unparent Bone and current bone keep transform How do I unparent bone from its parent bone but keep unparanted bone and its child bones transform and rotation? 

If I unparent bone, unparanted bone and its children change their position and rotation. I wish to keep it.

Will appreciate script for that if possible.
Control + A is a keyboard shortcut for applying a changed bone position as it's rest position in 'Pose Mode' (Maybe when you cut the posed position, it reverts back to it's rest position that you created it at?)

Control + A in object mode applies rotation, scale, and location.