The most common and most likely answer to this crossword clue is the 9 letter word RENUMBERS
R
E
N
U
M
B
E
R
S
Buddy explains!
The straight part
We know that "Assigns new labels to" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case assigns new labels to = renumbers.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 RENUMBERS mean?
RENUMBERS verb- To number again, to assign new numbers to.