Select Truncate from the Trend Line Functions menu to truncate a trend line. A trend line may be truncated only if it has been extended. For more information on extending a trend line, see To truncate a trend line using the keyboard, follow these steps: 1. Press 2. Press 3. Select Truncate. The selected trend line is truncated to the active end-point. To truncate a trend line with the mouse, follow these steps: 1. Position the trend line cursor over the end-point of the trend line you want to truncate and click the right mouse key. 2. Display the Trend Line Functions menu. 3. Select Truncate. The selected trend line is truncated to the active end-point.Truncating a Trend Line