Let’s say I am playing a Tome of Battle class that utilizes many stances and boosts. Can I ‘slow down’ a swift action and have it count as a move or standard action?
Example:
Swift action: use a boost maneuver.
Move: switch stance.
Standard: some kind of attack.
No.
Standard actions can explicitly be used as a move action
In a normal round, you can perform a standard action and a move action, or you can perform a full-round action. You can also perform one or more free actions. You can always take a move action in place of a standard action.
(Actions in Combat, emphasis mine)
No action, however, has a written rule saying it can be used for a swift action. Swift actions themselves can be (must be) used for immediate action, but that’s the extent of it. For reference, the entirety of the definition of swift and immediate actions:
Swift Actions
A swift action consumes a very small amount of time, but represents a larger expenditure of effort and energy than a free action. You can perform one swift action per turn without affecting your ability to perform other actions. In that regard, a swift action is like a free action. However, you can perform only a single swift action per turn, regardless of what other actions you take. You can take a swift action any time you would normally be allowed to take a free action. Swift actions usually involve spellcasting or the activation of magic items; many characters (especially those who don't cast spells) never have an opportunity to take a swift action.
Casting a quickened spell is a swift action. In addition, casting any spell with a casting time of 1 swift action is a swift action.
Casting a spell with a casting time of 1 swift action does not provoke attacks of opportunity.
Immediate Actions
Much like a swift action, an immediate action consumes a very small amount of time, but represents a larger expenditure of effort and energy than a free action. However, unlike a swift action, an immediate action can be performed at any time — even if it's not your turn. Casting feather fall is an immediate action, since the spell can be cast at any time.
Using an immediate action on your turn is the same as using a swift action, and counts as your swift action for that turn. You cannot use another immediate action or a swift action until after your next turn if you have used an immediate action when it is not currently your turn (effectively, using an immediate action before your turn is equivalent to using your swift action for the coming turn). You also cannot use an immediate action if you are flat-footed.
The only way to get multiple swift actions in a round is to use turn undead to power the divine impetus ability of the ruby knight vindicator prestige class from Tome of Battle.
