The most common and most likely answer to this crossword clue is the 7 letter word EMPANEL
I've seen this crossword clue in The Times
E
M
P
A
N
E
L
Buddy explains!
The straight part
We know that "put on list for service" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case put on list for service = empanel.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 EMPANEL mean?
EMPANEL noun- A list of jurors; a panel.
- To enrol (jurors), e.g. from a jury pool; to register (the names of jurors) on a "panel" or official list.