HomePod doesn't want to leave prior sources of music.

Sometimes my HomePod does not want to leave an input source. For example, if I was playing classical music (via voice command to HomePod) and stop HomePod, and then later I try to play Queen from my iPhone or laptop, the connection to classical music is still active. Occasionally I get a message asking me if I want to replace what is playing. Sometimes HomePod offers to sell me a multi-source upgrade. Sometimes, I just can't get my iPhone to connect to the HomePod. When that happens, I'll get a message that says I can't connect with airplay.

Is there a way to get HomePod to disconnect from a source of input and go to another source of input?