Well said Maria! Thanks.
Two other things we've experimented with that touch on that topic a little:
Keep the beat - Staying involved and continuing to provide a steady drum beat, even after a formal program finishes, to help fill the process void and give people a sense of the path forward.
Cherish champions, nudge for positions - Empowering those who are most inspired to help shift communal thinking. And, just as important, gently nudging for formalized roles to give those people dedicated time to advance the change.