The most common and most likely answer to this crossword clue is the 7 letter word QUIETUS
I've seen this crossword clue in The Daily Telegraph
Q
U
I
E
T
U
S
More clues leading to the result QUIETUS
Buddy explains!

The straight part
We know that "release from duties" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case release from duties = quietus.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 QUIETUS mean?
QUIETUS noun- A stillness or pause; something that quiets or represses; removal from activity.
- Death.
- Final settlement (e.g., of a debt).