The most common and most likely answer to this crossword clue is the 11 letter word TRANSFERRAL
I've seen this crossword clue in The Times
T
R
A
N
S
F
E
R
R
A
L
Buddy explains!

The straight part
We know that "conveyance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case conveyance = transferral.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 TRANSFERRAL mean?
TRANSFERRAL noun- A transfer, especially the making over of legal title or ownership to another