As a rule you would requalify a major change and maybe just
have a meeting to disposition a minor change (your technical
review board should have the authority and skills set to make
that call based on particulars).
But I know of instances where, although the manufacturer
says the masks and process are the same, the parts coming
out of two different fab lines -are not-. They may meet the
same datasheet, but there's a lot more to a part than its
Table I electrical parameters.
You have to own the decision process, and live with the
decision you make.