Save Swatch As
Use the 'Save Swatch As' command to save the current Swatch under a new path or name. The existing filename and path will be shown, if it is still valid, and then you can you choose a new filename, or navigate to a different drive or directory.
You can use the 'Save Swatch As' command to save the Swatch with it's existing name, by not altering the current details in the file-dialog, and just clicking 'Save'. You will be asked if you wish to replace the existing file with this one: just answer 'Yes'.