Your vulnerability to sunlight is reduced.
Prerequisite: Sunlight powerlessness or sunlight-related weakness.
Benefit: You can resist all dangerous effects of sunlight for a number of rounds equal to 1 + your Charisma modifier (minimum 1 round). After this time, if you are still exposed to sunlight, you take the normal effects as appropriate for your kind.
Source: Libris Mortis, page 26.