I think we get in the mindset in the church that we have to repent of our sins individually. While it is true that we must make right what we have done wrong, repentance itself is an overall process. If we are sinning intentionally, we aren't repenting. The definition of repentance is to stop sinning intentionally and turn our hearts to God. So yes we can repent after sinning intentionally. In fact, that is the very purpose of repentance. But the sooner we turn our hearts to God, the sooner we will receive the peace repentance and the atonement bring.