Old Divorce/New Marriage

What is the name of your state? FL

I got divorced in Michigan in 1993. My ex and I have now patched things up and been living happily together for 5 years. Can we call MI justice system to get original divorce annulled or vacated? If so, how do you go about it?

No. There's no such thing as "annuling" or "vacating" a divorce. You'll have to get married again.