Namehax is a tool that lets you bypass the flagged name screen on the league client. example. It does so by patching the string 'nameChangeFlag' in memory, causing the internal json deserializer to default the value to false. It has a hard-coded memory offset but you can use namehax.exe -d "nameChangeFlag" to dump a new offset, or any other string you wish to patch. You can then use namehax.exe -o <offset> to use that custom offset.
Just run namehax.exe after opening the league cient. Then login.
Head over to releases.
Make sure you have rust installed.
Run cargo build