You can sell Rights Entitlement in the cash segment of the Exchange, through the Kotak Securities Trading App / Website or Kotak NEO, just like any other Equity share.
Just like an Equity trade, you can choose to sell the REs at a price range someone’s willing to buy them at. Market forces in play will decide the price at which the REs will trade.
You can sell the REs till the RE window closure date.
To know more about Rights Issue, get the SEBI FAQs here, NSE FAQs here and BSE FAQs here.