Pronunciation Changes to Text-to-Speech Voice

I am using the Joanna Text-to-Speech voice for a project and was wondering if there's a way to change her pronunciation of certain terms.  Specifically, for my project, she needs to pronounce "delegate" with the short "a" found when stating the noun signifying a specific person/role.  For all but one instance of this word in my project, she pronounces it with the long "a" when stating it in the verb sense of this word.

Thank you for any assistance you might provide.