DBS Sell Signal appear on chart!

DBS chart appear Sell Signal, trader start to take profit. Chart shows 1) Big Down Bar 2) Reversal Candle Stick Pattern 3) Gap covered and 4) Increase in volume for down bar. If place stop order at $19.35 already stop out. If still holding it is better to take partial profit and let the rest of the position use run for maximum profit, use trialling stop to exit.