Hi, I think you can swap an ICANN domain and a .eth domain using a service like Unstoppable Domains or ENS. These services allow you to link your ICANN domain and your .eth domain, and use them interchangeably. You can also manage your domains using their tools and platforms. You can also transfer or sell your domains using their marketplaces or escrow services.
I hope this answers your question. If you need more details, you can check their websites or documentation.