Inspiration for jumper or cardigan if cut down the middle? And I might cut up and lengthen the inner sleeve seam, this creating more of a side seam at the same time so it's not quite so revealing on the sides.
A new life . pinner said she turned his shirt into a blouse! She made re-designed the neck opening, made a cut at chest level and gathered the bottom, redesigned sleeves, and narrowed and shortened everything.