Forum:How to make an NPC playable?

i would like to turn a pizza delivery person into a playable character to get a baby with the 'pizza appreciator' hidden trait, but i don't know how. may anyone tell me?
 * Get your Sim to fall in love with them, then you should be able to ask them to move in or you'll have to marry them. Then they'll move in and you'll be able to have a child with that trait. You can however still get the child with the Pizza Appreciator trait if the Pizza Delivery Sim is still an NPC but is a parent of the child. 19:07, July 23, 2011 (UTC)