Note: 'Oneself' is a third person singular reflexive pronoun.
1.
A speaker or writer uses ~ as the object of a verb or preposition in a clause where ‘~’ meaning ‘me’ or ‘any person in general’ refers to the same person as the subject of the verb. (FORMAL)
To work one must have time to ~.
PRON
2.
Oneself can be used as the object of a verb or preposition, when ‘one’ is not present but is understood to be the subject of the verb. (FORMAL)
The historic feeling of the town makes it a pleasant place to base ~ for summer vacations...
It’s so easy to feel sorry for ~...
PRON