as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
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buying a stock while the price is going down, and buy it at a lower price
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if you bought them, you can sell them.  that does not preclude you from buying again later. you might get yourself into a situation where you need to account for a so-called "wash sale" on your taxes, but your broker should calculate that and report it on your 1099-b at the end of the year.  there's nothing illegal about this though - it's just a required step in the accounting of capital gains for tax purposes.
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