Speaking with my editor hat on -- no, not touting for business -- I think it's important that you get the manuscript into reasonable shape before you look for a professional. This is where beta readers/writing groups come in.
If it's still rough, two things are possible.
1. Editors may turn it down, say they have a waiting list, whatever... but basically not want to take it on.
2A. Less scrupulous, less competent editors may grab it, do very little, send you a bill, and the end result may still be rough.
Or 2B. Less scrupulous editors may grab it because they see it needs a LOT of work and this could be their Christmas come early.
I recommend Carol Rose's Writing Wiki.
In general, terminology varies between US and British English, particularly about editors and how their role is described. If in doubt, come back to me or maybe Carol can help.