H1b petition expired,never traveled, Cap exempt possible?

I got my h1b petition approved in 2015 from my current employer. Never got the visa stamped or traveled to US as the role was unavailable. My petition was valid from Oct 2015 to Oct 2016.

Now my same employer wants to send me to US from a different account. My question is Can I apply for a cap exempt using the same petition? Is it mandatory that the person had to have got the visa stamped/traveled once to US to fall under cap exempt?