One solution might be a step-down step-up transformer unit that is made to operate small appliances where voltage is incorrect, these come in different sizes according to load, and they also can be reversed to step-up or step-down as needed. A smaller one might work OK for that soldering iron because it is not a large load. They usually have an assortment of adapter plugs for different countries. I believe PE sells them, if not then they can be found elsewhere, I have one that I bought some years ago, and I have seen similar units around. Don't leave the transformer plugged in to the house current when not in use, only plug it it when you have something to run with it. They draw current when idle.