Is there a function to call a feat so the impact provoques exactly that feat's effect?

EDIT: What about a function to reduce ConjTime or CastTime on an specific Force Power? I'm talking about a passive Force Power here (or always active).

Casting feat, yeah?
void main ()
{
object oFeatUser = OBJECT_SELF;
object oTarget = OBJECT_SELF;
talent tPowerAttack = TalentFeat(FEAT_POWER_ATTACK);
ActionUseTalentOnObject(tPowerAttack, oTarget);
}
Here, FEAT_POWER_ATTACK is feat constant taken from nwscript.nss
Also you may just use row number from feats.2da as this constant.
OBJECT_SELF is feat user, you may change from OBJECT_SELF to GetFirstPC(), this is player. Or GetObjectByTag("object_tag") to get object with the specified tag. So any object you want. the same is with OBJECT_SELF, but OBJECT_SELF is feat's target.
Hope it helps you.