Living forwards and changing the past

In Milan Kundera's The Book of Laughter and Forgetting, the narrator makes the following arresting remarks about the past and the future:

People are always shouting they want to create a better future. It's not true. The future is an apathetic void of no interest to anyone. The past is full of life, eager to irritate us, provoke and insult us, tempt us to destroy or repaint it. The only reason people want to be masters of the future is to change the past.

These remarks make an interesting contrast with what Kierkegaard famously says about life (in his journal for the year 1843):

It is perfectly true, as philosophers say, that life must be understood backwards. But they forget the other proposition, that it must be lived forwards.

The two passages are at least in tension, if they don't seem outright contradictory. If life "must be lived forwards", how can the future be "an apathetic void of no interest to anyone"? And if we can "change the past", doesn't that mean there is a sense in which life can be lived backwards? Both passages are insightful, and I think there is a way of understanding them so that they are not only compatible but also support each other.

First of all, we all know that the past cannot be changed, not literally. Our understanding of the past, however, can change. The past is important to us because "life must be understood backwards", and we can't help living forwards with a particular understanding of the past. It is the understanding of the past that counts, not just the past in itself. Although the same past can be understood differently, we can't change our understanding of the past at will. But we can change it indirectly, that is, by living forwards in a particular way. This is the sense in which people can "change the past" by being "masters of the future".

But why are living forwards and changing the past related this way? Because the past and the future form a narrative, and this is how we see our lives --- as stories unfolding. Different possible futures would result in different stories and hence different contexts in which the same past could be understood very differently. The past is already, as it were, written, but the future is, we believe, still open. The future in itself may be seen as an "apathetic void", but it is of great interest to us when seen as part of a continuous story.

What we want to create is not a better future (understood independently of the past), but a better life story --- better in the sense that the past can be understood in a way that makes it less likely to "irritate us, provoke and insult us, tempt us to destroy or repaint it".