Guide to White Soapstone Location
For allowing other players to summon you into their world.
Cardinal Tower Bonfire
First travel to the cardinal tower bonfire and make sure the wall has been blown up.
Head down the ladder and continue straight towards this man sitting near a gate.
Talk with him before going through the gate.
This is a trap/test provided by that man for the soapstone.
Go through the gate and kill all the enemies.
Once that is done run through the door they came out of and up the stairs towards the bridge.
Simply hop back down.
Talk to him once more and he'll reward you with the White soapstone.
If you killed Mild Mannered Pate before getting the soapstone you must wait awhile until his grave stone appears and pay 2,000 souls for a revive.