Templates for PC's

[cockroachman3178]

In the MM on page 177 it has a ritual for Pc's wanting to undergo the Lich Transformation.
I flipped to the DMG page 175 and read the Template section and it does not state whether are not Templates can be added to PC's.
I was just wondering whether PC's could take any of the other templates?

 

[Khaalis]

I don't think the ritual is intended for PCs, nor are any of the other templates. I get the impression that using the ritual is in effect retiring your character to the DM as a monster.