I happen to agree with Oil Field Trash.
Regarding Construction Law:
Getting a masters degree in CE is not going to prepare you for legal practice. Grad school prgrams in CE are very technical and will provide little if any real experience that can be translated into construction law. Real world experience working with contracts, change orders, and claims is going to be a lot more beneficial than what you learn in CE grad school. The time spent in grad school would be better spent either working in the field or going straight to law school.
First you should contact a lawyer in Michigan.
You would have to file some kind of motion to modify the divorce decree.
If the actual biological father has owned up to paternity, then the only issue is to correct the decree to accurately reflect the reality of the situation.
The Michigan equivalent to Federal Rule of Civil Procedure 60 is:
MCR 2.612 allows for relief from a judgment or order on specific grounds. These include mistake (2.612(C)(1)(a)); fraud, misrepresentation, or other misconduct of an adverse party (MCR 2.612(C)(1)(c)); and any other reason justifying relief from the operation of the judgment (MCR 2.612(C)(1)(f)).
A trial court's decision to grant relief based on this court rule is discretionary and will not
be disturbed absent an abuse of discretion. See Huber v Frankenmuth Mutual Ins Co, 160 Mich App 568, 576; 408 NW2d 505 (1987).
This can be accomplished with a motion to correct or amend the final decree due to mistake.