Reverse one's position and act on the furniture (4,3,6)
I believe the answer is:
turn the tables
'reverse' is the definition.
(thesaurus)
'one's position and act on the furniture' is the wordplay.
I cannot quite understand how this works, but
'and' could be 'n' (common abbreviation for 'and') and 'n' is located in the answer.
an anagram of 'the' is 'het' which is within the answer.
'furniture' could be 'table' (table is a kind of furniture) and 'table' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for turn the tables that I've seen before include "Change from losing to winning" , "Achieve complete reversal" , "Cause a reversal of fortune" , "effect complete reversal" , "Gain an advantage from an unfavourable position" .)