Replacing feature

Hey everyone, I‘ve been trying out homebrewing the past days and I came across a situation I still don‘t know how to handle. I‘m playing a Paladin but I created my own subclass which is more about a blood mending/necromancy oathbreaker paladin. My question actually is quite simple. the normal paladin has the bonus action „lay on hands“ and as it is taking up a lot of space on the character sheet I wanted to get rid of it and replace it with a homebrew version of lay on hands but I cannot figure out how to do that as the „feature to replace“ section cannot find any matches.

I set the homebrew version up as a class feature inside my subclass. So not a class feature option. If that makes sense

Is it even possible to replace a lvl1 action like lay on hands?