Is there a way to accent an “e” to make it sound like “ah?”

I echo other respondents in expressing frustration at the vagueness of the question.

In English, there are two diacritics that can be applied to <e> to change its pronunciation.

<è> is occasionally used to ensure that the <e> is pronounced and not silent.

Grave accent

The grave accent, though rare in English words, sometimes appears in poetry and song lyrics to indicate that a usually-silent vowel is pronounced to fit the rhythm or meter. Most often, it is applied to a word that ends with –ed. For instance, the word looked is usually pronounced /ˈlʊkt/ as a single syllable, with the e silent; when written as lookèd, the e is pronounced: /ˈlʊkᵻd/ look-ed). In this capacity, it can also distinguish certain pairs of identically spelled words like the past tense of learn, learned /ˈlɜːrnd/, from the adjective learnèd /ˈlɜːrnᵻd/ (for example, “a very learnèd man”).

I make a point of writing learnèd. Very very few people do.

<ë> properly is used to split up a digraph, so the preceding vowel and the <e> are pronounced separately; e.g. Zoë /zoʊi/. However, <ë> was occasionally used for the same reason as <è> was. So (Brontë family) Brontë was a much more posh-looking rendering of the Irish surname Ó Pronntaigh, than the normal anglicisation Prunty or Brunty. Tolkien picked up that function of <ë> in his renderings of Elvish languages.