The most common and most likely answer to this crossword clue is the 9 letter word RE-ENLIST
I've seen this crossword clue in Independent
R
E
-
E
N
L
I
S
T
More clues leading to the result RE-ENLIST
Buddy explains!

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 RE-ENLIST mean?
RE-ENLIST verb- To enlist again.