The change from a bullish to a bearish structure is called „Change of Character Down “ (ChoCh).
A ChoCh Down is created, when the last higher low is broken down and the market starts to create lower lows and lower highs.
The change from a bearish to a bullish structure is called „Change of Character Up“ (ChoCh).
A ChoCh Up is created, when the last lower high is broken up and the market starts to create higher highs and higher lows.