Kudaku |
The full text on spell resistance special ability is listed here: http://www.d20pfsrd.com/gamemastering/special-abilities#TOC-Spell-Resistanc e
The relevant text is as follows:
A creature can voluntarily lower its spell resistance. Doing so is a standard action that does not provoke an attack of opportunity. Once a creature lowers its resistance, it remains down until the creature's next turn. At the beginning of the creature's next turn, the creature's spell resistance automatically returns unless the creature intentionally keeps it down (also a standard action that does not provoke an attack of opportunity).
A creature's spell resistance never interferes with its own spells, items, or abilities.
Ie you can cast helpful spells on a creature with spell resistance, but unless that creature takes a standard action to lower its spell resistance first (turn off its shields, so to say), you need to roll a SR check.
Spell resistance is a bit of a double-edged sword. For the most part it's beneficial, but it can really bite you on the ass too. I've seen characters bleed out because the cleric trying to heal them was unable to penetrate the character's SR. Coincidentally one of the (relatively few) situations where it's a good idea to have ranks in the Heal skill even though you have stabilize on your 0th level spell list.