Florida law requires payroll deduction unless both parties agree otherwise and a judge signs off on it. You'd have to get the person who receives child support to agree in writing to stop the deduction then get a judge to ratify the stipulation.
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Ordinarily, and Income Deduction Order can only be terminated when the support obligation (current and delinquent) ends or by agreement of the payee. Florida child support laws have changed, and now require every support order to specify a presumed termination date, when the IDO automatically reduces the amount withheld or expires (usually as each child reaches majority). If your Order pre-dates 2010, it most likely does not contain this automatic provision.
There is one other possibility. The Florida Department of Revenue is beta testing a voluntary system where your child support is automatically deducted from your bank account, the way you pay other bills. The payor has to sign up for the program, and then can ask the court to terminate the IDO. If there is not enough in the account to pay the support, the IDO is reinstated. Check with your Clerk's Office to see if the program is available in your Circuit and to learn more about how it works.
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The law gives the right to an "income deduction order," not exactly the same as "garnishment" but pretty close, to the payee spouse upon her request. So just about the only way around this is if she will agree to not have it in place. So no, you can't "opt out," of the IDO just because you don't like it.