In the section on your app or web, select the relevant IPO you’ve applied for. You can then tap the Bid Details dropdown and tap Modify or Cancel to modify or cancel your application

Important: 

• Only bids upto ₹2 lakhs can be cancelled or modified before IPO the bid window closes. Bids more than ₹2 lakhs can’t be cancelled but can be modified only to increase quantity or price
• While cancelling or modifying bids can be done before or after accepting the UPI mandate, once the IPO subscription is closed you cannot cancel your bid