Open the PhonePe app
Tap your profile icon
Go to Bank Accounts or Payment Methods
Select the bank account you want to use as primary
Tap Set as Primary or Make Primary
Confirm the action with your UPI PIN if prompted
If the option is not available, remove the current primary bank account and add the desired account again
Make sure the new bank account is linked to the same mobile number and is UPI-enabled
If needed, update the UPI PIN for the new primary account
