What does “sich umziehen” mean in German, and how is it different from “umziehen”?

One German verb, two different meanings, largely decided by a single reflexive pronoun. Ich ziehe um means “I’m moving house.” Add “sich” — ich ziehe mich um — and it means “I’m changing clothes.” A German daily-routine song for beginners uses the reflexive sense: ich ziehe mich um, “I get changed,” sitting right between waking up and getting dressed.

The pronoun isn’t the whole story — with a direct object, jemanden umziehen can also mean changing someone else’s clothes, as in ich muss das Kind umziehen (“I need to change the child”). So the real contrast to hold onto is ich ziehe um (I’m moving) vs. ich ziehe mich um (I’m changing my own clothes) vs. ich ziehe jemanden um (I’m changing someone else’s clothes) — same verb, three pictures depending on what follows it.