In a few circumstances, you can help an ally accomplish a task or perform better. However, additional help isn’t beneficial in some cases, such as when a character tries to fool an item utilizing Use Magic Device. In other situations, only a limited number of characters can help at once, such as when breaking down a door or turning a winch that has one small handle. DMs can limit how aid another is used as they see fit for given conditions. When multiple creatures can aid the same ally, the bonuses they provide stack. If you aid someone performing an act that would normally provoke attacks of opportunity, then the act of aiding another provokes attacks of opportunity in the same way.
AID ANOTHER FOR ABILITY CHECKS
You can help an ally achieve success on an ability check by using aid another, taking the same amount of time that the ability check normally requires. To do so, you make the same kind of ability check, simulating a cooperative effort. You must roll for the check—you can’t take 10 or 20. If the result of your check is 10 or higher, the ally you’re helping receives a +2 bonus on the ability check. You’re essentially providing favorable conditions.
AID ANOTHER IN COMBAT
In melee combat, you can help an ally attack or defend by taking this standard action to distract or interfere with an opponent. If you’re in position to make a melee attack against an opponent that is engaging an ally in melee combat, you can attempt to aid that ally. To do so, make an attack roll against AC 10. If you succeed, you can choose to give your ally one of two benefits—your ally gains either a +2 bonus on his next attack roll against that opponent or a +2 bonus to AC against that opponent’s next attack, as long as that attack comes before the beginning of your next turn.
AID ANOTHER FOR SKILL CHECKS
You can help an ally achieve success on a skill check by using aid another. In cases when a skill restricts who can achieve certain results, you can’t use aid another to grant a bonus on a task that your character couldn’t achieve alone. A character who doesn’t have the trapfinding class feature, for instance, can’t use aid another to help a rogue on a Disable Device
check to find a magic trap.
When you’re able to aid another on a skill check, you do so by making the same kind of skill check, taking the same amount of time that the skill check normally requires. You must roll for the check—you can’t take 10 or 20. If the result of your check is 10 or higher, the ally you’re helping receives a +2 bonus on the skill check.
If you have 5 or more ranks in a skill you’re using to aid another, you can grant a higher bonus. For every 10 points your check result exceeds 10, the circumstance bonus increases by 1. To determine the circumstance bonus quickly, simply divide the helper’s check result by 10, round down, and add 1.
At the DM’s option, this rule can also be extended to using the aid another action in combat to improve an ally’s attack roll or AC. Any character who has a base attack bonus of +5 or higher can grant a greater bonus on an ally’s attack roll or AC as described above.