Exhaust manifold bolt removal??

Questions for you gurus out there. I have a blown Exhaust gasket and am planning on replacing it this weekend. Do you remove the 4 Bolts when the engine id cold or should you warm it up before removing. I know that on the reinstall , you tighten and then warm up the engine and tighten a tad more. Just do not want to strip the aluminum on removal. Thanks in Advance for any input you all have…