"He is changing you."
Translation:Tá sé do d'athrú.
When the object of a verbal noun is a pronoun, you have to change the structure to this: Tá x do y VN. x is the subject, and y is the possessive pronoun. So, here you have Tá sé do do athrú. But, because the second do comes before a vowel sound, it becomes d' - Tá sé do d'athrú.