A person can withdraw their plea of guilty on no contest only in certain circumstances.
What it comes down to is needing to prove that you didn't know something then, that you do know now. This may be that new evidence has been found. It may be that you were misinformed about the law, or the amount of time you were facing by your lawyer, or it may be that you were misinformed about the strength or weakness of the governments case.
In any case, you will need to prove that the new information is so important to making the decision of whether or not to plead guilty that it would sway the decision of a reasonable person, if your situation, to change their mind.
The burden of proof is on you and the presumption of the court will be to deny your request unless you meet that burden of proof. The reason is simple. The Court doesn't want people pleaidng and changing their minds all the time. This would be a waste of judicial resources, and could potentially clog up the system. If you genuinely have a good reason to change your plea (beyond that you changed your mind) you should request to withdraw your plea.
So you have 6 felony counts of commericial burglary and no previous criminal record and you are getting a worse deal than your Co-Def wit criminal histories? That is just awful. I don't know the full facts of the case, but if you had ineffective assistance of counsel, there is a large possibility of getting your plea withdrawn. But, withdrawing your plea prior to sentencing is one thing, and if it goes through, your case re-opens again and a bail will be placed on you.
There is obviously a lot more too it than you describe. You can't get that kind of time for a commercial burglary and you don't say what charges and enhancements were filed on the other case(s). There is a stiff penalty for committing a felony while out on bail for another felony. Nothing you describe here is grounds for appeal or withdrawing your plea. You can't just withdraw your plea because you changed your mind. If you were misinformed about what kind of time you were facing and then pled guilty based on that, you could withdraw your plea, but that seems very unlikely.