Moving toilet

[Neils]

Hi, I want to move my toilet about 2m along the same wall. I know my easiest option is to run a new soil pipe internally and box it in, but ideally I'd run it along the outside wall.
My question is how do I connect a new plastic pipe to the existing iron pipe? Is it possible to rotate the existing branch 90° making it easy to attach the new pipe, or will the whole lot have to be replaced with a new plastic branch etc...

Thanks.