How do I change a unit to a different unit altogether...

[xCIA_BlackThorn]

I want to change the (Player) Soldier in to a Sniper in mid game...how would I go about doing this?

Is it even possible?

[THobson]

The only way I know to change the body of a unit is by editing mission.sqs.  That is not possible within a mission, so I don't think it is possible to do what you want.  

[c_jay_ie]

Alright, I've an idea. Maybe you can camcreate a sniper, make him player, and then delete the soldier.

Would that work?

[macguba]

No.

The player unit is defined in the mission editor:  you can't change it during the game.   The workaround is to make a mini-campaign.   If you can figure out how to "make him player" you'll be a Flashpoint hero because nobody has done it yet.    Search the forums for dozens of threads about this, it is one of the commonest questions.

Your method is correct for changing the clothes of AI soldiers, except that you should use createUnit:  camCreate is for static objects, not AI.