Backup codes

Oh golly - the number of things named "back-up" is daunting.  I travel a bit internationally, change phone cards constantly and must use "backup codes" to provide two-factor verification.  I've almost used all of my codes up.  How can I get a new crop of backup codes?  When I've checked on the community, I see information about keeping the codes safe, but nothing on getting new ones.  (or tons of info on backup procedures, but that is not the kind of backup I need.  Please help.