Are there any Sith that went from Dark to Light?

I have never read of any Sith going from the Darkside,and yes I mean full Sith Lord or apprentice to light side.

here I am, and the above is my question

No, the Jedi killed them first.

SO Iam assuming that this has never happened before

Revan and Vader were both full sith as was Visas Marr and they all turned. Visas was a sith before becoming a Jedi. Ulic Qel-Droma also turned to the light side.

I thought Revan only turned and wiped all his memories so that he could infiltrate and destroy a Jedi resistance or was that all in my head

Revan turned to the dark side and then had his mind wipped and given the option of being light or dark he chose light. After his mind was wipped he had the choice to fall again and didn't and instead brought Shan back from the dark side as well.