There is so much change in "For the Union Dead," and a good deal of frustration with a lack of change, too. In both cases, it seems that the transformation (or the lack thereof) is a negative thing. Change for the better? Not in this case. Lowell takes us through the current construction (read: destruction) of South Boston, and the decay of all of the old, worthy stuff (the aquarium, for example). This kind of change seems to be bullying the old important stuff to make way for something shiny and new (and meaningless). On the flipside, the underlying feeling of racial oppression doesn't seem to be going anywhere. Bad times all around.
Change is all good. Lowell gives us all of these examples of Boston's transformation to illustrate our progress as a country. Yay, us.
There is huge contrast between the physical transformations in this poem and actual societal change. Lowell thinks the physical change is useless, even destructive, and that the real change needs to come to the people, and not necessarily the place. So, get it together, people.