Answer:
The change in the sentence should be themselves instead of theirselves
Step-by-step explanation:
This sentence uses a reflexive pronoun, which is a kind of pronoun that we use when the person that does the action of the verb is also the one who receives this action, it is a very common way of expressing many common activities since it may be applied in different situations, besides the correct spelling is themselves using the root word them as the object pronoun not their as the possessive adjective.