orcad layout gnd net
zip all the files in your current folder.
correct the net in the schematic. and do autoeco. layout will immediately tell you that netlist has changed and will give you eco options.
AutoECO/Override Attrs may be useful for you.
following are the ECO options
ECOs command (Tools menu)
Use the ECO commands to forward annotate a printed circuit board from OrCAD Capture for Windows (or another vendor's schematic design application) to OrCAD Layout for Windows.
AutoECO selectively communicates information from Capture to Layout, or from one printed circuit board to another. In other words, when bringing data into Layout from Capture, you can choose the appropriate AutoECO option to annotate only the schematic data that has changed. This way, you can avoid inadvertently overriding board data that you do not want to change. You can also choose from two AutoECO options that communicate information between printed circuit boards.
The first six commands in the menu transfer data from Capture to Layout during forward annotation. The last command, AutoECO/Net Attrs, communicates information between printed circuit boards.
AutoECO – the basic AutoECO. It adds and deletes parts and nets but it does not change footprints, part locations or net properties.
AutoECO/Override Attrs – adds and deletes parts and nets, overrides net properties and part properties. It changes footprints but does not change locations of existing parts. Components that are no longer needed are deleted.
AutoECO/Override Coords – merges new components and connections with an existing board. It overrides all of the placement coordinates in an existing board, and reconciles all components and nets with the netlist.
AutoECO/Override All – merges new components and connections with an existing board. This ECO reconciles all components, nets and properties with the netlist, and also moves all components to the netlist coordinates. Components and nets that are no longer needed are deleted.
AutoECO/Add Only – adds nets and components, but does not change anything that exists on the board. This option is useful when the board is near completion and you wish to add some parts (for example, a bypass capacitor). Properties on existing components are not updated.
AutoECO/Add Override – adds new components and nets, and overrides component and net properties. Unused components and nets are not deleted.
AutoECO/Net Attrs – transfers net attributes such as width, weight, spacing-per-layer, width-per-layer, and reconnection type from one board to another.