A modernizer is a person or thing that makes something more modern or up-to-date.
Modernizers are usually seen as helpful and positive, making things better for the present time.
Examples:
The modernizer updated the old building.
She is a modernizer because she makes old things new.
The modernizer changed the old town into a new one.
The modernizer made the old car into a new one.
The modernizer changed the old world into a new one.
He is a modernizer because he makes old things new.