don't release any pressure. you can remove it on full pressure and leave it in the corner a few weeks.
you can also just seat the lid on a newly filled keg with 30psi, and then leave it to sit at room temp if you have no room or know for a fact it needs to age a bit.
I drain kegs slowly enough that they condition at 44F for months and months.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10