Switch positions from time to time (2,3,3)
I believe this clue is a double definition.
'switch positions' is the first definition.
(a switch might be on or off)
'from time to time' is the second definition.
(I've seen this before)
(Other definitions for on and off that I've seen before include "Switch choices" , "From time to time, not continually" , "spasmodic" , "Occasionally" , "the two sides at Old Trafford?" .)
'time to time' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'switch positions from' is the wordplay.
I cannot really see how this works, but
'switch' could be 'off' (I've seen this in another clue) and 'off' is found in the answer.
'from' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?