How Do I Rotate The Near Clip Plane

I’m trying to create a seamless portal but when entering from a side the near clipping plane clips with the portal being able to see the other side, the only solution I could come up with (other than making it 3d but that came with a bunch of other issues) was to rotate the near clipping plane to pe parallel to the portal . . . but idk how, earlier I used something called camera.projectionMatrix, but I don’t really understand Matrix4x4.