Advice for Changing Co-op Management Cos?

Our mid-size, low-frills co-op in manhattan is evaluating switching management companies. Has anyone driven this process before? What surprises do you wish you knew before you started? Looking for: - Any tips on how you found and vetted alternate management companies (suggestions welcome for companies to talk to or to avoid) - Any tips/preparation on smoothing over the actual process of onboarding, e.g. collecting archives, untangling accounts, switching technical systems, communicating to shareholders. Couldn't find old threads easily in search, but links to existing ones are also welcome.