Let’s Talk Strength

I have an old technical document that made sense when I wrote it, but reading it now is a completely different story. There are long sentences everywhere, and even I have trouble following some parts. I started considering professional technical writing services because I want the information to be clearer. Has anyone had a technical document rewritten before? Did the writer keep the important details while making it easier to read? I would really like to know how the process worked for someone with similar problems.