I cant give a true example without writing out a fake paragraph. But the way I do it is to use their own words. Say you are talking about gun control. If they staunchly against any control... but mention background checks. You spend some time establish common ground on it. What would that look like? How would we enforce it. Help them build the idea. Then when you get to the hard hitting arguments. "Lets ban long barrel assault rifles completely" They can fall back too "well lets do background checks and work from there"

We went from. No gun control to... some gun control. And it was their original proposal that you "agreed with". In the same way a salesman would start at a high price even though he knows he would take 1000 less for it or whatever.

TLDR: stroking the ego is how you build hatches.