Pathfinder's magic rules say that a creature with "special resistance to magic" can voluntarily fail a saving throw against a spell.
Voluntarily Giving up a Saving Throw
A creature can voluntarily forego a saving throw and willingly accept a spell’s result. Even a character with a special resistance to magic can suppress this quality.
But the rules for spell resistance seem to imply the opposite, that a creature would need to drop its spell resistance before being affected by the spell.
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).
I'm confused how these rules interact. If a creature with SR hasn't lowered their SR, can they voluntarily fail the save without a caster level check from the caster? Or does "special resistance to magic" refer to something other than SR?