The most common and most likely answer to this crossword clue is the 10 letter word DELEGATION
I've seen this crossword clue in Financial Times
D
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Buddy explains!

The straight part
We know that "Passing over" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case passing over = delegation.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 DELEGATION mean?
DELEGATION noun- An act of delegating.
- A group of delegates used to discuss issues with an opponent.
- A method-dispatching technique describing the lookup and inheritance rules for self-referential calls.
- A contract whereby the original debtor substitutes a new debtor in his stead, with the creditor’s permission.