Generating random sequences and changing single notes within the pattern

Hello, I am relatively new to Max and am working on a new project I would like to use Max in. I am creating sequences to be sent out via MIDI to hardware and want to create a system where there are random numbers tuned to a scale (which I have a patch built for already) that then create a sequence of 4-8 notes that can be repeated until a message is sent. I would like to then slowly swap out each note of the sequence with another that is generated in turn and over time the whole sequence would change. Not sure where to start on the storing of sequences and the swapping of the notes.

Thanks in advance!