replace serface mount ic
If the micro is not to be reused, then for a QFP or TQFP package what I do is this:
take a utility knife with a new blade and gently cut the pins close to the pckage. I just put the blade on the pins at about 45 deg angle, along the side of the package, and push down slowly until it cuts through 2-3 pins at a time, being careful not to push too hard to cut traces underneath. Usually I set the blade such that only the tip is exposed, which gives more protection, since the knife usualy touches the package and stops before the blade ever touches the PCB.
When all the pins are cut on all four sides, I remove the pins with the soldering iron (they just adhere to it) clean the pads using copper braid and install the new micro.
It is a good idea to practice it on a scrap board, until you get the hang of it.
If done properly, the board will not be heated nearly as much as it is with a desoldering station.
Soldering the new part is done simply with a fine-tipped soldering iron, under a microscope or a magnifier.
I do not have a solution for BGAs.