Mainstream leftists need to start taking seriously the idea of abolishing the police entirely. This institution cannot be reformed. It is made up of the most extreme right elements of our society and built around oppression and racism.

If I need to call someone for help or protection it needs to be an institution which I know is explicated and openly on the side of the people against power.

The police cannot be reformed into such an institution, they exist to protect power and property against the people.

If a white middle class person calls the police on a poor black person, they need to know the police will side with the black person, by default.

This won't happen with a sanitized police force, but only an independent community defense organization, like the Black Panthers.