how to draw a section plane at an angle

I have a cube and I want to create a section plane that goes trough the middle of 3 edges that have a common point. After this I should be able to erase the smaller solid and keep the bigger one.

Any help would be appreciated.

P.S. If needed I will attach an image to be better understood.

It sounds more like you want to slice this solid. Is this correct?

Posting an image or the drawing is always helpful.

You're completely right, slicing is perfect for what I want.

I was just wasting my time with section plane.

Use UCS 3 points then draw a larger cube then subtract then UCS W all done.

Use UCS 3 points then draw a larger cube then subtract then UCS W all done.

That's how I used to do it before learning about the 3point option for slice.