Not surprisingly, Amazon always pushes their in-house services (Kindle, Amazon Music, Audible, etc.) anyway they can. After a recent update, you can now replace Amazon Music as the default music library with Spotify or as the default station service with Pandora or iHeatRadio. Just open the Amazon Alexa app, go to Settings > Music & Media > Choose default music services and select your preferred services (You can also do this on http://alexa.amazon.com/).
So what does this change? This changes is the need to specify “on Spotify” every time you want to stream music. Instead, you will need to say “on Amazon Music” when queueing up a song to play it through Amazon’s music service. This is great news for us Canadian owners of Echo who don’t have access to Amazon Prime’s music service.