The well-known feeling that we can have "second thoughts" about an action or decision extends even to the brief time between making that decision and taking the action, during which we might reflect on more of the potential consequences.
This is of course easiest when the decision is to act at some future time. But there always is a temporal sequence in free will and almost always a bit of time for reflection.
Some philosophers think of this as the freedom to "veto" an act of the will. And some have argued that it might be the only freedom. If we don't have Free Will, we might have Free Won't. [need references] It is of course really nothing different from the rapid contemplation of consequences, the careful consideration of options, the de-liberation of alternative possibilities that goes on when the Macro Mind makes a quick decision about anything. It is just more obvious when there is plenty of time between de-liberation and action, when the mind gets to reflect on "What If..."
We can think about second thoughts with a modern communications metaphor. The mind, especially the frontal lobe of the brain where much reasoning and planning takes place, has a powerful capability we might call an "Instant Preplay." And from the information theoretic standpoint, the mind with second thoughts has already embodied the information about having made the initial decision. It is that information that we can replay over and over as needed.
Recent research in neuroscience with brain imaging identifies significant activity in the frontal lobe when a decision is vetoed. [reference]
Note that this does not mean a loss of adequate determinism in the will. The decision to send the question back to the Micro Mind for consideration of even more alternative possibilities does reintroduce indeterminism and freedom into the overall process of "free will." But in no way does it compromise the adequately determined Macro Mind.