It all turns dark very quickly when used for brood. I don't replace unless it's damged. Some people try to rotate all the comb out every five years. In other words they date the frames and try to swap out two frames out of every box every year. I've never done this.
Assuming your question is how to get the frames out of the hive, the easiest time to do this is in the early spring when they are empty from winter. The next best would be to pull out frames that are full of nectar or honey during the flow and extract them (if you use chemicals feed them back otherwise keep it for honey). I would NOT pull frames that have brood in them.
Assuming your question is, instead, how to recycle a frame and put new foundation in it, that depends on how the old foundation was put in. If it's nailed in with a cleat or it's waxed into a groove, and what kind of foundation it is. Sounds like you have wired wax and it's probably nailed in. Based on that assumption, I'd pull the cleat, rip out the old foundation (keep old brood combs seperate from cappings when processing because the old brood combs will actuall soak up wax sometimes). If it's horizontal wired you may have to cut the wires. If it's vertically wired you can usually just pull them, although a pair of pliers may help the process. If the bottom bar is grooved use an old small screwdriver to clean out the groove. If the bottom bar is split it is difficult to get the wax out without breaking them but you can try. When you are about to put the frames back in, put the foundation of your choice (I"d be using 4.9mm small cell) back in using the method of your choice. Be sure to use a different cleat than the one that came from that frame so the nail holes don't line up. It will hold much better. Plastic is usually just snapped in and if you have a cleat you'll need to nail it back in. Wax has to be put in and nailed, unless you have a grooved top in which case you'll want to wax it in.