I would also agree with this Pk scroll.
First of all, even though you don't want to PK a player there are times that you need to when there are players that will KS you even you say stop and will countinue to annoy your leveling and farming.
I suggest that it can be bought at item mall for PP only and it will just reduce the PK points by specefic amount not reset by 0.
For example a scroll that will reduce PK points by 100 or 200. Depends on the item.