How to change player's body (package, scale)?

So what I want to do is make a script that changes one player's body when the game starts. I want it to change to the normal body scale and 1.0 package, but I can't find a good way to do this. I've tried welding body parts to the character, but depending on what package they're wearing, it messes up. I've also tried deleting the player's body parts, then putting the new ones in, and then using MakeJoints(), but nothing seems to work. I would appreciate help if anyone knows how

For Packages I dont know, Why dont you do a google search?

As for size, the humanoid object of R15 players has these 4 values:

BodyDepthScale, BodyHeightScale, BodyWidthScale, and HeadScale

Change them as you please in a script