If you have an ellipse (as a projection) on the sphere surface then revolve is not going to work. Well you could do a certain “revolve” but it would be far too complex.
If you want to keep the ellipse as a basis for your bump sphere… (well, bump ellipsoid I mean) you have to make so many additional steps it wouldn’t be worth to.
So, I think you want to stick with a “sphere on top of a sphere”. Thus boolean the two spheres will do the job correctly.
But… you have to be careful. So, plan first how big R=? your big sphere is going to be.
Where on its surface you would want the small sphere (r=?) should be placed. maybe a little spherical bump? If so create your sphere from the center of the big one (it will save you later troubles). Then make a straight line form the center of the big sphere to the point where you want the bump’s center to be. Move the small sphere along the vector of that straight line (lock the move with the TAB button to match the vector). Works great here, 3 to 5 steps.