Offset flange in lead pipe

I have a lead pipe with what looks like just a flared lip set in a concrete floor in my basement. I moved the wall out behind the toilet flange so I need to put an offset flange in. What is the best way to accomplish this? I have seen those flanges that just push in the existing pipe and seal with an o-ring but they say they are incompatible with lead because of the lead stretching but since my pipe is encased in a concrete floor will I be able to use that product?

Thanks

offset

I have never seen an offset flange that I would consider to be compatible with lead. In fact, with lead, if the riser is tall enough you may be able to open the concrete in front of it and bend it to the new location.

I was hoping I woudnt have to jackhammer out my foundation. Why is there no compatible offset flange? What is the problem with lead?