TLDR; If I understand the OP correctly, to answer the question, yes; sometimes people
bloodline their characters. :3
Generally speaking, the original character virtually ceases to be and the new character inherits their rank and sometimes some of their artifacts. They usually also get a massive bio to boot.
If you do it at Knight, no one cares, because anybody who isn't an Apprentice can promote you on a good word alone and no minimum RP interaction limit, and so there were never any restrictions either way. If you do it at Master, you're probably best off informing an administrator prior to requesting the change, as said, and it isn't always the preferable course of action because it can be seen as a form of handwaving.
Sometimes it's much more enjoyable to reroll a brand new toon at said rank than having to start over from scratch just for a fresh, new change to the RP storyline. It can also be somewhat of a challenge, having the rank but not yet the respect or perks. ^^