Accent marks on nouns [duplicate]

English does not use accent marks basically

You're rather incorrect there; quite a few English loanwords ('borrowed' words) do possess diacritical marks , for example: naïve & entrée. However, it is completely acceptable (for everyday situations) to drop the accents.

Certain names — which are proper nouns — are not usually considered English words (& hence not bound to English grammar rules) and whether or not you should accent somebody's name depends on how they will accept it. Accents are largely a part of someone's name and you ought to, if possible, accent it.

There is no reason why you should not do that (unless you're unable to), because it's essentially almost equivalent to misspelling.