Watch the Same Old Thing online guitar lesson by Brad Carlton from Chord Studies: Pedal Tones Vol. 1
We're still playing a vi-IV progression but now we are switching to the key of F major, so Dm is the vi chord and B♭ is the IV chord. We've got the same idea happening as before, because whenever you move from a vi to a IV chord, only one note changes. This time we've got A moving up to B♭ as you'll notice throughout the progression.