Reducing a position means selling part of the stocks held. To reduce a position is to sell the stocks you hold. Reducing the number of stocks in your hands (analogy to a warehouse) does not necessarily mean selling them all. Selling everything seems to be called closing a position.
To reduce the stock position is to sell a part of the stock. It is an operation to take part of the profit to secure some profits when the market outlook is uncertain, or a strategy to withdraw some funds when the position is too heavy. .
Reduce positions when volume rises: When a stock rises, there is a large amount of trading volume, and buyers and sellers compete. If you pay attention to the principle of caution, you can reduce positions and wait and see.