There are areas in a song that can change keys many times without changing the song's key signature. They are called key areas and are explained in the attached PDF :

https://www.dropbox.com/s/fr3y5ungopeuzdd/Key%20areas.pdf?dl=0

This is how those out of the song key signature chords are explained. Basically any chord can come after any other chord, even if the modulation is abrupt.


Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware