The most common and most likely answer to this crossword clue is the 12 letter word INTERCHANGED
I've seen this crossword clue in The Sunday Telegraph
I
N
T
E
R
C
H
A
N
G
E
D
Buddy explains!

The straight part
We know that "Switched" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case switched = interchanged.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INTERCHANGED mean?
INTERCHANGED verb- To switch (each of two things)
- To mutually give and receive (something); to exchange
- To swap or change places
- To alternate; to intermingle or vary
- To act as or carry out an interchange (noun, senses 2, 3).