How to remove rebar passing through an inaccessible pipe
They make root cutters for cutting plant roots that have grown through pipes, but they are made to cut roots, not steel. I'm not aware of anything that is specifically designed for this. Maybe you could get a steel cutting blade made for a root cutter. You would then still have to get the pipe lined afterwards to seal the holes. This would be a pretty difficult and expensive process, and it would not be guaranteed to work.

Overall, it will probably be the best and cheapest option to cut the concrete around the pipe, fix it properly, and replace the floor. If the repair blending in is of concern, you would want to cut at existing saw joints, if the concrete will be covered, you can just cut and replace the immediate area of the repair.