You can't change it - you can only be accepted into it.
So not only you have to do something extraordinary, someone from the caste needs to like what you did.
Or you could be born into it...
You can't be born into it, and the system has traditionally honoured thousands of 'normal' people that have been nominated, usually by their peers, for doing work in their field or community.
https://www.gov.uk/honours-committees
As you can see, some of them are themselves honours recipients, and some are not.
In no sense is this a self-awarding organisation - and the only reason there are so many recipients on the committee is because honours are given out to just about everybody who has achieved anything of note.