Rephrasing my mother's question
My mother asked her children, "What do you want to change?"

Explanation
When reporting someone's words, it is important to use the correct reporting verb (said, asked, etc.), tense (usually past tense), and pronouns (changing the pronouns to fit the new context). In this case, the original question "What do you want to change?" is being reported, so it becomes "What do you want to change?"

Using reported speech
My mother asked her children what they wanted to change.

Importance of reported speech
Reported speech is used when we want to convey what someone else has said without quoting them directly. It helps in maintaining the flow of conversation and is a common way of relaying information in both written and spoken communication.

Conclusion
By rephrasing the original question using reported speech, we can effectively convey the message without quoting directly. It is essential to follow the rules of reported speech to ensure accuracy and clarity in communication.