Good luck, as it is nearly impossible. The problem is the glue used (when it is not stitched) has separated from the material lining. This happens with the jacket get wet sometimes but usually from too much heat in dry cleaning or steaming. Once this happens, any method you would think (ironing, pressing or steaming) would correct it, usually makes it worse. Better suits are stitched and don't use glue.
P. Henry, June 2019
