Click on 'Mint' on the navigation bar.
Click on ‘Expired Assets’ and select the synthetic asset that you want to burn and redeem the collateral, click on 'Redeem'.
Select ‘Redeem assets’.
Select ‘Fully redeem assets’ and click ‘Redeem & Exit Position’.
Approve the transaction.
You can see that your pxAsset is returned to the contract and PERL is added to your wallet balance.