Once an asset belongs to a particular address, the asset issuer cannot forcibly take it away from that address. However the address holding it can publicly 'burn' it by sending it to the chain's burn address, which can be retrieved from the burnaddress field given by the getinfo command. The burn address has no corresponding private key, so it's provable that assets sent to that address cannot reenter circulation. Any node can see how much has been sent to the burn address by adding it with importaddress.