The present invention is directed to a release mechanism for removing and/or releasing a locking cap from the head of a bone anchor in situ. The release mechanism includes a sleeve, an anchor coupling member and a knob. The anchor coupling member is located within the sleeve and the knob engages both the anchor coupling member and the sleeve. The distal end of the sleeve and anchor coupling member engage the bone anchor causing the bone anchor to splay from the locking cap. A driver may be inserted into the central bore of the release mechanism to release any further threaded engagement of the locking cap and the bone anchor.