Used H1b for a year and then employer withdrew.

[nbrao87]

I haves used my h1 b visa for a year from 2016 oct to 2017 oct. My employer withdrew it. Later i changed my visa status to h4ead and was in USA since then. I have not not left the country since then. My question is 1.when can i apply for reinstate of my visa status.
2. Is there a certain time limit within which i have to apply for reopening my H1?