Ideas how to convert this flange to a single 3" Pipe

Or take your 3" piece, squish it, then cut it in half length wise. Then add in a "center" piece, with the 2 radius' on the outside of this center piece...in essence, widening the 3" squish to become the size of the flange. Your center piece will need to be pie shaped, as to adapt the flange dimensions to a round 3" piece of tube.