Try loosening the packing nut around the stem and under the turn handle, spray it and the packing good and turn it. Or turn off the hot water at the valve above the hot water heater. Be careful of bleed over of water from from the cold side if someone opens another single handle faucet while you are working on this. Or else turn the water off at the meter. Replace the stop valve under the sink and maybe you should replace both while you are there. They get corroded up over time and they are cheap.
Sorry just reread your post and I not sure if you are talking about the faucet itself and or the stop valve under the sink I discussed above. The faucet should still have a nut to unscrew (depending upon the type and brand) to remove the stem. If you are replacing the sink, maybe you should replace the faucet also.