Sim's Supernatural Trait Change

 Hi! I just got Sim's Supernatural and may I say I really enjoy the game. But my Sim has just gotten married to one of the in-game Sim's that did not create, Joe MacDuff. So I went into "edit town" and moved him into my house, but then I realized that he has the trait "coward" and he is scared of the skeleton maid that you can buy, "Bonehilda". All he ever does is run away for her and it takes away from his mood. So I had to lock her in the bathroom. I really want my maid back because she always helped with the baby and the rest of the house, but I don't want her to keep frightening Joe. So, I was wondering if there was any possible way that I could change Joe's traits to where he is not scared of her and I could get my maid, that I paid a lot of Simoleons for, back. Please contact me to help instruct me how to change a Sim's traits. I would really appreciate it. This would help tons!