There are many Jazz standards where a 2 5 1 progression is followed by another 2 5 1 progression in a key whose 1 chord is a tone (major 2nd) lower. In this situation, chord 1Maj7 of the first key becomes chord 2min7 of the next key.
This means that if you are improvising over the progression, all you have to do is change the chord from a Major 7th to a minor 7th by lowering the 3rd and 7th degrees a semitone. Here is an example.
To help you become more familiar with this type of change, it is a good idea to practice alternating between a Maj7 and a min7 chord on the same root note with arpeggios, modes, and improvised lines as shown below.
Once you are comfortable alternating between the two chord types, the next step is to repeat the process through all the keys. Try progressing down a semitone until you reach the same note an octave lower, then go up by semitones, then around the key cycle both ways, up and down in major 2nds, minor 3rds and major 3rds.