Yes, you can withdraw/ release the unutilized amount which has been marked as Hold for trading. Once the funds are released, it can be withdrawn from the bank.

For example,

Funds in  Bank account = Rs.1,00,000,

Amount marked as Hold for trading = Rs. 60,000,

Value of Orders = Rs. 40,000.

In this case, Rs.20,000 out of Rs. 60,000 is not utilized. Therefore, you can release the Hold to the extent of Rs. 20,000 only and then withdraw.