First you will have to remove the handle , where there will be a set screw you will have to remove to remove the handle. Then Their is a retaining ring, or nut that must also be removed , then you will need to pull up using a cartridge puller or a vice grip style wrench. first the water must be turned off and you must relief the pressure by opening up the hot and cold and let the remain water trickle out ,then go turn the sink on in another part of the house . The reason why you need to do that is to break the natural suction or back pressure that is holding the old cartridge into place. Depending on how old the faucet it the cartridge might be frozen or stuck into place and you will need a cartridge puller tool.
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