When painting a home's interior, Is there a way to blend two different colors?

This can be done but would be very tricky. You would have to roll the paint on and as you paint, starting with one color and then add the other color to the roller pan as you want to transition. Keep adding the new color until that is all you are painting with. Might have to stir the color into the pan or even clean it out when you want strictly the second color.