If you're already on Coinbase, you can cash out there by sending your Lumens over. Otherwise, you can go through one of the Stellar exchange frontends and conv

If you're already on Coinbase, you can cash out there by sending your Lumens over. Otherwise, you can go through one of the Stellar exchange frontends and convert the lumens (there are a few institutions set up to accept lumens and convert them into a token tied to the value of a fiat currency (these tokens are still part of the Stellar network) -> real currency via bank transfer)