There are many different ways that people accomplish this on surprisingly large boats, it really comes down to how mechanically inclined you are and how daring you are. Am I correct in thinking that a soling has a keel stepped mast, it has been a while since I have looked at one?
The simplest method is to gather a few friends and carefully pull it up. This is one of the least controlled and more prone to failure methods. It is amazing how hard to control the top of the mast it is even on a small boat. Personally, I would not try this method but I am positive that someone has successfully done it.
Other methods generally involve some form of a pick point higher than the CG of the mast. A commonly used one is rafting three boats together and taking out the center boat's mast.
Another variation on it that was also mentioned above is finding a bridge or dock gangway to do it from. I have done this and have several friends who do it on a regular basis. As long as you are not breaking the law, have a good place to belay to on the bridge, can tie the boat off well under it and there is adequate water, this works just fine. There is a story which may or may not be legend about some people in Beverly failing to read the train schedule properly while doing this... You mention having the boat move away from the bridge in one of your comments, I would not do this as the mast needs to be lifted straight up. You want to control as many variables as possible.
Another one is to go find a pier that has a lifting boom on it. Many commercials piers have them and also some public piers have them. This is very straightforward and the same as using a crane.
It is up to you to make a judgment call as to what is safe. It is amazing how hard to handle a mast is. Breaking your mast or worse, hitting a person with it isn't worth a few saved dollars but it can be done for free safely with some thought.