Are there different routes one can take to officially change rank in the Army system?

Demotion and erroneously paid at old rank can and does happen....two separate systems and it takes a personal action for BOTH>
Id venture to say it always gets noticed at some point and once the personal action is properly completed, you can bet the Gov will recover ALL of the erroneously paid funds

Sure if you would like to change your rank, just look at the UCMJ, break a few of the rules and your rank will change in no time, this is perhaps the quickest way. The more time consuming, but more rewarding way is to do your job, complete whatever requirements are necessary for the next higher rank, and be recommended for promotion... ;)

what does this have to do with title of discussion?