My 99 regal needs new sparks plugs and I was able to replace the front three but i was wondering if there was a way to turn the engine to make the back three more accessible?

You could undo the two front wishbone engine mounts and rock the engine forward but really not necessary to replace the rear bank plugs. Clearance gained really is not significant. I have no problems. Just takes some patience and the right hand tools.

I removed the spark plug by the alternator by reaching under the alternator. I got to the other two rear plugs by going over the top of the engine. Put some padding on the dogbones to protect your knees and climb on up. Pulling the spark plug boots is the hardest bit. I gave them a squirt of WD40 to get the boots to come off.