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.


Tips on how to fall asleep in a living room chair:
1- Be old
2- Sit in a chair

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