When a signal candle is not triggered by the subsequent candle you may decide to move your entry down to the level that the subsequent candle closed at. This process can be repeated until the point that the signal candle is invalidated. However, not every subsequent candle qualifies for trailing your entry down.
Keep in mind that overall trend needs to still be going in the direction that you want to be taking a trade. If the subsequent candle is looking bearish when you're looking to long, trailing your entry is strongly discouraged. The stop loss level always remains the signal candle low (for longs) or high (for shorts). Also keep in mind that you size your position accordingly, because the lower candle wick entry changes your risk management.