The short answer is that you clone the PCB footprint, edit it and save it as a new part with a unique name. Note that you can assign the same pin number and name to more than one pad on a package. The complete answer is: We recommend that you; 1. always produce a PCB from a schematic; 2. always produce a PCB footprint for every part that is on or forms part of the PCB; 3. always produce a schematic symbol for every part that is on or forms part of the PCB; 4. always assign - and check the pin mappings for - the appropriate PCB footprint to the schematic symbol; 5. never edit things like holes and footprints in the PCB directly. That way when you want to produce the PCB all the footprints will already be correct before you click `Convert to PCB...` and after that if you update the schematic (for example to swap from a 3 to a 4 pin socket), when you click `Update PCB...` or `Import Changes...` there will be no changes made directly in the PCB, that those actions will then overwrite. For more information about this please see (2) in: https://easyeda.com/andyfierman/Welcome_to_EasyEDA-31e1288f882e49e582699b8eb7fe9b1f then for details of how to create or edit Schematic Symbols and PCB footprints, see: https://easyeda.com/Doc/Tutorial/SchematicLibs.htm#Creating-the-Schematic-Libs https://easyeda.com/Doc/Tutorial/PCBLib.htm#Creating-The-PCB-Libs You can edit existing Schematic Symbols and PCB footprints by clicking `Clone`. Then save them with a unique name and a full description (Supplier, Supplier part number, package, Manufacturer, Manufacturer Part and Description, setting all of these attributes or parameters to visible in the BoM). Once saved into the library, search for them again then do `Modify` on the library entry to add a description and include a link to the Manufacturer or Supplier Device page and a link to the Manufacturer or Supplier Datasheet. * Here's an example to **SHIFT+F** search for, select, then study the library entry and click `Edit` to see the above information is associated with them: Symbol: **STL140N6F7** Package/footprint: **PowerFLATtm5x6** Note that this package has multiple package pins mapped onto the same symbol pin number. * This is how you deal with the pin numbering of your 4 pin socket.

Thanks for the reply. Can I also do this by adding a pad and changing the size?

`Can I also do this by adding a pad and changing the size?` You *can* do this if you are designing a PCB without starting from a schematic but as I have just tried to explain, if you start your design with a schematic and then convert that to a PCB, if you then manually add or edit a footprint directly in the PCB and *then* make and import *any* changes from the schematic, **those manually applied changes to the PCB will be deleted**. Try it in a simple example PCB and see what happens. For more, have a read of (4) in: https://easyeda.com/andyfierman/Welcome_to_EasyEDA-31e1288f882e49e582699b8eb7fe9b1f :)