Historically, some philosophers have attempted to reduce time to something else, say change or the causal nexus. It's interesting to note that this cannot be done if presentism is true. For to reduce time to something else requires giving a nontemporal account of the "wholly earlier" relation between events. But if presentism is true, there never exist two events one of which is wholly earlier than the other. For if one of them is present, the other is not. And only present events exist given presentism.
Now, of course, the presentist has a way of talking about non-present events. She can, for instance, use the temporal modal operators WAS and WILL. However, she cannot do so in the course of reducing time to something else, since WAS and WILL already presuppose time. The presentist must take time to be primitive, thus.
In particular, this means that Aristotle, who attempted to reduce time to change, cannot be consistent if he is a presentist.