You can use heat and pressure to stretch out leather shoes. Moisture helps to stretch out shoes if the leather does not release in response to heat and pressure.
Put either the wearer's feet, layered up in thick socks, or a shoe stretcher inside the shoes. Make sure the shoes are very tight. Set a hair dryer on high heat and direct the heat at the tightest part of the shoes. Have the person wearing the shoes wiggle her toes or jiggle the shoe stretcher gently. Put the shoes on without the extra socks to see if they fit. If the shoes are still tight, mist a thin layer of liquid shoe stretch on the tight areas and repeat the stretching step.