Free to come together, turning it upside down (5)
I believe the answer is:
untie
'free' is the definition.
(I've seen this in another clue)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for untie that I've seen before include "Undo, unfasten" , "Release bindings or shoelaces" , "Undo, unlace" , "Separate" , "Open a knot" .)