Solder sucker to desolder the component and clear the hole. Alternatively, put a jeweller's flat-bladed screwdriver under one end of the resistor to apply a little gentle tension and then melt the joint, and repeat for the other end, but if you then have a blocked hole, melt the solder and put minimum pressure on the lead when pushing the right component in to avoid lifting the track off the PCB. Heating up resistors soldering them shouldn't hurt them.
I generally populate boards by putting a few components in at a time, soldering them and then snipping the leads. Resistors first, then diodes, then capacitors, followed by IC sockets and then transistors - the lowest profile components go in first so you're not hampered putting them in by taller ones.