To stretch patent leather shoes, take a plastic bag, and fill it halfway full with water. Seal the bag tightly. Place the bag in the shoe, and put the shoe in the freezer. As the water freezes, it expands, fills the available area and presses on the edges of the shoes to make them bigger. Put the shoes on and relax as they defrost and mold around your feet.
Heat is also effective when trying to stretch patent leather shoes. While wearing a pair of thick socks, put the shoes on. Put a hair dryer on the hottest setting, and direct the air toward the tightest part of the shoe. As that area heats up, the leather becomes pliable, and it stretches around your feet.
Another option is to fill the too-small shoes with a layer of rubbing alcohol. Use a spray bottle to apply the rubbing alcohol, and put the shoes on while still wet. Wear them until the alcohol dries, and repeat the procedure until the shoes are roomier.
There are also commercial sprays that are designed to help the patent leather relax and stretch. A professional cobbler may also be able to make a patent leather shoe bigger.