Intervene in the moments that matter.
As a leader, you can use your position of power to destabilize the manager who is gaslighting.
By doing so, you signal to the gaslighter that you are watching and aware of their actions and putting them on notice.
If you see that a manager has excluded an employee from a meeting, make sure to invite them and be clear that you extended the invitation.
Document what you’re observing on behalf of the employee who is the target of gaslighting.