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Each team is allowed to waive a player without having their salary count toward the salary cap or luxury tax. One player can be waived prior to the start of any season from 2011–12 through 2015–16. It can be exercised during the seven days that follow the July moratorium. Each team is restricted to one "amnestied" player during that time. Only players signed prior to 2011–12 are eligible. Teams can claim an amnestied player at a reduced rate, with the waiving team responsible for paying the balance of the contract. The team with the highest bid acquires the player. If unclaimed, the player becomes a free agent. Teams over the salary cap can only acquire an amnestied player if he becomes a free agent and the offer would be limited to the veteran's minimum contract.
Source: http://en.wikipedia.org/wiki/NBA_salary_cap#Amnesty_clause
-- If your team hasn't used its amnesty clause yet you may choose to release a player and his contract.
