Sue, I just had a quick lookie and I think you can do what you need in the preset manager. (Edit--preset manager). In the menu that pops up use the drop down menu to select 'pattern' and you should see all your current patterns in the preview window. You can select one or a combination (hold the shift whilst selecting multiple patterns) and then click on 'Save set'.
This then saves a new set including the patterns you have chosen. Now you have a new .pat file that is available to you.
This seems to be true for tool presets, brushes, etc
hope that helps