Li Shenron
Legend
Bolstering Undead: An evil cleric may also bolster undead creatures against turning in advance. He makes a turning check as if attempting to rebuke the undead, but the Hit Dice result on Table: Turning Undead becomes the undead creatures’ effective Hit Dice as far as turning is concerned (provided the result is higher than the creatures’ actual Hit Dice). The bolstering lasts 10 rounds. An evil undead cleric can bolster himself in this manner.
It looks like there is only turning check and not turning damage roll (and I think this is quoted also by DotF).
If the result is greater than the undead's HD, the result becomes the new equivalent HD for turning purpose only.
Does this apply to ALL undead within range or can you bolster only 1 with each bolster attempt?