In a simultaneous declaration, each player must declare his intent at the same time, without knowing what any of his opponents intend. This is often done by taking chips under the table, hiding them in one's hand, and then all players opening their hands at once after everyone has chosen. For example, no chips in hand means that the player declares "high", one chip means "low" and two chips means "swing". In a consecutive declaration, each player verbally declares in turn, and later players can therefore use that information to make their decision.
The usual rule in split-pot games with a declaration is that half of the pot is awarded to the highest hand among those who declared "high", and half is awarded to the lowest hand among those who declared "low". If no player declared in one direction, then that half is awarded in the other. That is, if all players declared low and no player declared high, then the low hand wins the whole pot instead of just half. If a player declares "swing", he must have both the highest hand and the lowest hand clearly, with no losses or ties in either direction, to win the whole pot, otherwise he wins nothing (even if he would otherwise have won half). This rule (or one like it--sometimes a "swing" hand that ties for best in one direction and wins clearly in the other may still be allowed the winning half) is necessary to prevent all players from simply declaring "swing" every time.
Another use of the term "declaration" is the act of declaring how many cards a player intends to draw in a draw poker game. It is common for all players to declare their draw intentions before any actual cards are dealt, after which all replacements are dealt at once. This protects the players against marked or accidentally exposed cards.
Other uses include declaring the intended amount of a bet or raise ("A verbal declaration in turn is binding" is a common rule in casinos), declaring the value of a hand upon showdown and declaring how one chooses to receive a card in a choose-before Roll your own game. The rules of each of these games may specify how a player is held accountable for these declarations. \n:See also : Poker