I just tackled this exact task 2 nights ago with my SF 6P.... I suggest you remove the bezel from the body, and place it in a bowl of hot water...let it soak 5-10 minutes (this allows any possible loctite to release). I then used a pair of needle nose pliers, and spread them wide enough to fit into 2 slots on the ring..... turned the pliers counter clockwise and off came the bezel ring. You then have access to the lense and can replace it with the new one.... I did not apply any loctite when I reinstalled the bezel ring, for my guess is I might be doing this again one day. 😀
Hope this helps, and best of luck!