If you need to reinvite a user to your account, if for example, you've sent them an invite and they were on leave, and didn't manage to activate their account before they got back, you can do that via, "My users" top right menu.
Anybody with a yellow "invite expired" status, you can reinvite. You do that simply by clicking the resend invitation button in the right most column. That person then get a fresh email invite, with a link which they can click to get their account set up.
