Second @jhutson re: contacting an attorney. Presumably if it is legal, unanimous consent from the current residents is required. If not unanimous then some big majority.
With 7 homes, you should be asking yourself -- can you get unanimous consent from these stakeholders to change the legal designation of the park (if it is really legally a "senior park"?)
If not, how much will you have to pay them to get your way? The problem is, as @Greg points out, the current residents lose some equity if you let in the riff-raff. They may want compensation in exchange for agreeing. Then there is the lone-holdout problem.