At the moment there are some similarities, but basic fingerpicking patterns and normal chord sequences can be reused. I'd say, do something very different with the vocal melody and you'll be fine.
If you're swapping chords, one thing that you can do is choose overlapping chords (not sure if that is the right term). E.g. D minor is D, F, A, and F major is F, A, B. Substituting one for the other will give a different, but similar, sound.