Here is something that works for me, so long as the new part and the old part have the same PCB footprint. First add the new part to your schematic and connect it in parallel with the part you want to replace. Don't delete the old part yet, though. Now go to the PCB Board
and place the new part on top of the part you want to replace. You'll get a couple of DRC errors, but you can ignore them for now. Finally, co back to the schematic and delete the old part (the one you want to replace. You can move the new part to the old part's spot if you want, and you can use F10 to change the new part's reference designator to what the old part was using. Now go back to the PCB Layout
. The old part should be gone, the new part should be in its place, and your routing should be intact. I hope this helps.