The Spotify account that you have linked will be saved to your account. In order to disconnect it, you'll need to sign out of the Spotify web player. Follow these steps:

1. Log in to your account here.
2. In a separate browser tab, go to open.spotify.com.
3. Log out of the Spotify account that opens.
4. In the Soundtrack browser, go to Your music.
5. Click on create, select the desired options, and log in to your new Spotify account.