Ask a jazz man what it means to “work through the changes” and they’ll tell you that it is a way of taking a chord progression that is defined in the head and weaving a melody of your own into it. Jazz may seem unstructured, especially to listeners used to hearing a pop tune or an orchestral piece and sometimes the structure may be so loose (or in some instances, so complicated) that it is hard to hear, but there is almost always an underlying scaffold of some sort that holds the piece together. The most common form for jazz is a head, numerous choruses, and a restatement of the head as an ending. There are some variations; a short intro may be added, or the head may be repeated between the choruses or between soloists as a sort of palate cleanser before the next guy starts to work, but the basic form is still followed. The choruses are based on the chord progression and/or the melody that is introduced in the head and are usually a set number of measures in length–12 , to 32 bars is standard. The soloist creates his statement over the changes. My point here is that there is a structure that keeps everything from flying apart and yet, in the best pieces, the structure does not restrict the soloist;, it grounds him and gives him a starting place. The structure also inspires him, catapults him into the stratosphere and provides a safe haven to return to.
I’ve noticed, in my own life at least, that then happiest I been are the times when I’ve been challenged by change. The changes were not always looked for, or even welcome, but even after the most painful ones, there was a period of newness and challenge, of learning and exploring that recharged me. The worst times have been when that challenge is no longer there and boredom has set in. It is at those times that I look for the foundation, return to the key, strain to hear the original melody and progression, to return to ground so that the changes can hurl me skyward once again.