Returning back to USA on H1B approved remaining period after 6 years

Hello, I’ve H1B approved in 2013. But i used only 7 Months and then i moved back to India to pursue other career option. But now i want to return back. Initial H1B Visa expired in 2016. But i was reading some forum that i can still re-capture my remaining period. Can any one please guide me on how re-capture H1B will work in above scenario ? Thanks!