Carefully, you have to vent the pressure but this is not supposed to be done to atmosphere you should take it to a mechanic if you dont know what your doing. The pressure is some parts of the AC system and do some serious damage to you.
If you have a broken or severely leaking hose the pressure will be a moot point. Just make sure you don't come in contact with the freon remaining as you vent the system and disconnect hoses. Freon contacting skin is instant freeze and it's as bad as a burn. Be sure to replace the reciever/dryer as well since the desicant pack will be full after you open the system. When all is re-assembled, then take it to a shop to be evacuated and recharged. DO NOT recharge w/o evacuating. Air and moisture in the system will make it inoperative and negate all the work you did.
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