If you have a 5-string, you probably don't need to de-tune unless you want/need to go lower than B (some guys drop the B string down to A to match the lowest note on the piano). If you are a 4-stringer, you may want to consider de-tuning or investing in something like a Hip Shot X-Tender key. Otherwise, you can play those lower parts an octave higher and just do it in standard tuning.