Changing owners corporation manager is a decision the owners make at a general meeting. In practice it means passing a resolution, giving the current manager the notice their contract requires, and having the outgoing manager hand over the building's records and funds. Strata Plan manages the handover. We've handled this handover many times since 2004, and we tell you what to expect at each step, so your committee isn't guessing.
You don't need anything to be wrong to switch. Plenty of committees move simply because they want a manager who has more time for their building and genuinely cares about it.