Any church can leave at any time in most denominations. And, only a few denominations practice significant control over member churches. As I noted earlier in this topic, the difference between a IFB church and a Presbyterian church leaving the denomination is just a little paperwork.
Even the difference between a Roman Catholic church and an IFB church is mostly tradition, not the authority of the denomination. The Catholic church has a priest and hails Mary not because the Roman Catholic Church told them to, but because it's a Catholic church. (The selection of the priest, though, is by the RCC.)
In Protestant denominations, the function of a denomination isn't control of a local church, but to provide services to the local church.
