''The amendment to the policy would limit overseas travel by any individual employee to ninety days at most per year.''

この文の by は文法上どのような役割となっているのか教えてもらえませんか？
Could you teach me the meaning of ''by'' in this case?

查看翻譯

"by" is telling us that the limitation of oversees travel is being applied to "any individual employee"

if you were to replace "by" with "of" it would have the same meaning.

"The amendment to the policy would limit the over seas travel of any individual employee to ninety days at most per year."


(this is hard to explain so let me know if you still don't understand)