If I sign up for an exchange within Obamacare, can I cancel it if I don't wish to continue having insurance mid-way through?

What happens if I sign up for an Obamacare plan (I live in NY), and I decide that I don’t want the coverage any longer, either for financial reasons, or simply because I don’t like it (for lack of a better way of putting it). I guess I just want to know what my options are here….

I imagine it’s specific to the provider, but…if you’ve any insight, I’d love to know.