Reflexive pronouns are also used in the set
phrases by ___ self and by ___ selves).
These phrases have two meanings. One is
without any help:

I don't need any help. I can do it
by myself.

His homework is perfect. Did he do it
by himself?

Did the children clean their rooms
by themselves?

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The other common meaing for by ___ self
and by ___ selves is alone:

Bobby is only six years old, but he flew to
London by himself.

Do you have roommates or do you live
by yourself?

Do you want some company or would you
prefer to be by yourself?

Reflexive pronouns can also be used to add
emphasis. In this situation, the meaning is
is something like "personally":

I myself don't believe him.
(Personally, I don't believe him.

Yes, Jane is leaving. She herself told me.
(Jane personally told me that she is leaving.)

You yourself must be present. No one can
represent you. (You must be present
personally. No other person can represent you.)

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For this use of reflexive pronouns, the
pronoun can also be at the end of the sentence:

I don't believe him myself.
(I don't believe him personally.)

Yes, Jane is leaving. She told me herself.
(She told me personally.)

You must be present yourself. No one can
represent you. (You must be present personally.)