If you encounter or witness a crypto pump and dump scheme, you can report it to the relevant authorities or platforms. For example, you can report it to the Securities and Exchange Commission (SEC) in the US, the Financial Conduct Authority (FCA) in the UK, or the Australian Securities and Investments Commission (ASIC) in Australia. You can also report it to the exchange or platform where the scheme took place, such as Binance, KuCoin, or CoinCodex.