If you own the node with the channel they're in, then yes you can do it by closing the channel. If it's a custodial lightning wallet like Alby or Wallet of Satoshi, then you need to swap them from lightning to on-chain using something like Boltz. I don't advise letting 0.21 BTC accumulate in a custodial wallet though. 😂
Discussion
Of course. My question was hypothetical. But I don’t think I understand how all of that works. I need to sit down and think about it. Thanks anyway
No problem. Lightning is pretty ingenious. A "channel" is simply a multisig bitcoin UTXO shared between you and your channel partner. When you open a channel from your own Lightning node to another node, part of that UTXO balance is controlled by you, and the other part is controlled by your channel partner. Every time a transaction is made using that channel, the relative balances are updated to reflect who controls what. The protocol is designed so that only you can spend your portion, and your channel partner can only spend their portion, and at any point either one of you can decide to "close" the channel which will send your balance to your bitcoin wallet, and the channel partner's balance to their wallet, minus any on chain transaction fees. These channels (UTXOs) are linked together by the lightning protocol to facilitate payments from the originating node to the receiving node. When you use a custodial lightning wallet, you simply have an account with whoever runs that node, and your "balance" in your custodial wallet is not actually anything you possess but rather (if they're honest and trustworthy) part of one of the channels on their node.