Free (Phish) jam (D to Bb)
Sorry I don’t have diagrams made for this one, but you can grab the info elsewhere on this site. The chords switch from D to Bb. Both are major chords, and you may notice that there is no single mode that works over both chords. But there’s an easy way to navigate this change. And fortunately the chords don’t change all that quickly.
I tend to treat the D chord as D mixolydian, and I’ll also mix in a little blues, using some D minor pent here and there–what some people call “mixo-dorian” (I just call it blues). When the Bb comes, I treat it as Bb lydian…which is made up of the same notes as D aeolian. So one way to think about it is changing from D mixolydian to D aeolian. Only two notes change in this process–you flat the 3rd (F# becomes F), and you flat the 6th (B becomes Bb). And even better, Dm pentatonic actually works pretty well through the whole thing too.