He means this:
function cl_SetVehicleOwner ( theVehicle, thePlayer )
local oldVehicle = getElementData ( thePlayer, "cl_ownedvehicle" )
if isElement(oldVehicle) then
-- unlock old car
removeElementData ( oldVehicle, "cl_vehicleowner" )
removeElementData ( oldVehicle, "cl_vehiclelocked" )
removeElementData ( oldVehicle, "cl_enginestate" )
setVehicleLocked ( oldVehicle, false )
-- set vars for new car
end
setElementData ( theVehicle, "cl_vehicleowner", thePlayer )
setElementData ( theVehicle, "cl_vehiclelocked", false )
setElementData ( thePlayer, "cl_ownedvehicle", theVehicle )
setElementData( theVehicle, "cl_enginestate", true )
end