It should not be necessary to uninstall and reinstall the client in order to point it at a new account. Instead just click on Accounts in the Jive toolbar, then on Add Account in the lower left, and on Jive. Enter the credentials for your live community, and you should be able to authenticate and connect there. You can keep both connections, if you want to continue to post to both. I have my Outlook connected to several communities and it's never been an issue.
I just figured it out moments ago. Thanks!