Yeah, you'll need to check the manuals for your synths.
If they don't have an onboard function for that, you might be able to change their tuning via MIDI.
Note that some instruments might use cents rather than Hertz, where 0 cents probably means 440.0 Hz. In that case, you would need to calculate the desired offset in cents:
cents = 1200 * log (hertz / 440, 2)
If the desired Hertz were 432, then the offset in cents would be -31.7667 cents. Depending on the precision allowed, the result might be a little bit different than 432 Hz:
hertz = 440 * 2 ^ (cents / 1200)
For instance, -32 cents (or rounded to the nearest whole cents) would be 431.9418 Hz, whereas -31.8 cents (or rounded to the nearest tenth of a cent) would be 431.9917 Hz.