When you give someone a promotion (which is a job with a higher title or pay), you shouldn't say "I promoted Carlos..." That sounds too self-centered, like you're trying to take the spotlight away from this person.

It's better to say "Carlos has been promoted..." In this way, you can describe a person's promotion without saying who did it. In general, when you don't want to say who did an action, you say "___ was ___ed".