lightning network – Transfer Outbound to Inbound liquidity – Umbrell node

I have an Umbrell node, and few channels open with outbound liquidity as I don’t know how to open inbound liquidity. I want to close one of my outbound channel that is mostly offline and transfer this outbound liquidity to inbound liquidity on some other address. I want to do it on a lightning network so I don’t have to pay a fee for closing a channel on the main network and I want to make it without leaving sats there.
This is a basic question that probably everyone that learning by himself confronts…
I doing this because I want to learn and I want to deploy my BTC so it can be beneficial for the network. I also put UPS so I can be online even in the event of a blackout. I already try to ask on Twitter, directly Umbrell, and some other places but no one of my 43 followers have responded with an answer. I am by myself in this without a computer science background and I need some help.
Just for the info, my address is:
033df1379a959f8b2c7a2faaba61ed83be199e6ac2dae765b16a8cdf7f7d56399c@57d2nl5yk7sycn4zf7mktwnyrfa3x4oczzuwbvfemzlgagrmws6gcdqd.onion:9735

Thanks