Amory's tutorial explains transacting using an offline wallet:

https://bitcoinarmory.com/using-offline-wallets-in-armory/

Note that I sign transaction offline. To put it simply your address is a private key, from which a public key (the public address) is derived. You can have one client, synced to the Blockchain, displaying your balanced, able to make transactions.

Then you take that transaction to an offline computer or source and sign it, take it back to the online computer and transmit it to the network. /roughly, see the other link for better information