What a Lawyer Can't Do
Guarantee results such as a dismissal of a case or a reduction of case - A lawyer cannot promise a result. It is ethically prohibited as well as impossible as a practical matter. No lawyer can tell you what a DA or judge or jury will say. If a lawyer does promise you a result, run the other way and report them to the State Bar.
Charge a fee contingent upon a result in a criminal case (i.e., a dismissal or reduction of a case) - You cannot tell a lawyer that you will pay them only if they get your case dismissed or reduced.
Suborn (encourage or facilitate) perjury or make misrepresentations to the court - You cannot ask your lawyer to submit false information to the court or to the prosecutor or anyone else for that matter.