1.119 used as objects of prepositions

If the subject of a clause and the object of a preposition refer to the same person and the clause does not have a direct object, you use a reflexive pronoun after the preposition.

However, if the clause does have a direct object, you usually use a personal pronoun after the preposition.

Note that if the clause has a direct object and it is not obvious that the subject of the clause and the object of the preposition refer to the same person, you use a reflexive pronoun. For example, 'The Managing Director gave the biggest pay rise to himself'.