Tell your story in a blog or video (something with more impact and information than a short social media post). And don’t forget more traditional outlets like press releases and media interviews (local news, podcasts, etc.). Tell your story across multiple channels, and tell it often.
You can make this process more memorable (and painless) by teasing people that a change is coming. This includes external and internal communications. Internally announcing the change becomes particularly important if you have more than a dozen employees, multiple locations, and a broad distribution footprint.