Altium Remove Component Overlay but Leave Part Designator?
right click on one Part -> Find similar objects 
ensure that "Select Matched" is checked (ON)
Object Kind = Component: Same
Then set "Lock Primitives" to false
right click on one Track on the layer you want to change -> Find similar objects 
Object Kind = Track: Same; Layer = Top Overlay: Same
Then change the layer and track with of all the selected components