Yes, you can cancel the online subscription for Lightroom and buy standalone Lightroom as upgrade if you have any older version of Lightroom.
If you don't have any older version of Lightroom then you need to buy complete license for it.
Thank you So much for replying.
Now I have this LRCC 2015 Which was my subscription
Do I need to Buy the standalone version or Buy only upgrade for this ?
I need to mention one more thing out here I don't have a Credit Card Got a Debit Card
If your subscription has expired Or Cancelled, then you need to buy complete version of Lightroom 6.
Please check all the payment modes on the Product page