I press my own jacket lapels. Roll up a cotton t-shirt into a tight cylinder, insert it into the recess of the lapel, hold the iron a few cm from the lapel and fire plenty of steam at it. Then sweep the iron over it, lightly at first, then with a bit more pressure, always holding the lapel in the shape I want for it. Seems to work ok. Obviously I've adjusted the plate temperature to suit the fabric I'm pressing. Sometimes this shit is just common sense.