。
She adjusted her schedule to fit his.
Literal
She [topic-は] his [genitive-の] schedule [to-に] her-own [genitive-の] schedule [object-を] matched.
The pattern Xを Yに合わせる ('fit X to Y, match X with Y') uses 合わせる ('combine, match, fit together'), the transitive partner of 合う ('fit, match'). The thing being adjusted takes を, the standard it's being matched to takes に. 自分 ('one's own') is the reflexive pronoun — refers back to the topic of the sentence (彼女).