Ken help

So my lucy doll is on older ken body (2006 maybe 2005) and was a toy my sister used to play with so I am always worrying about her other arm falling off (its only a matter of time
) So I was hoping I could take off her head perhaps put on a new ken doll body (I dream of a day when I can put her head on a Barbie body). Any recommendations or tips on how I could do this?
For reference she is a Derek from twelve dancing princesses.

For reference she is a Derek from twelve dancing princesses.