How to Modify Existing Positions in MT5 (Mac)
In MT5, you can add limit and stop orders to your existing positions or modify already placed closing orders. There are mainly two methods to make changes:
・Change from the Position Window
・Change on the Chart
How to Modify from the Position Window
This method involves displaying the position window where you can modify your existing positions.
There are mainly two ways to display the position window:
・Display from the Toolbox
・Display from the Chart
Displaying from the Toolbox①
Right-click on the position you want to change within the 'Trade' Tab in the Toolbox and select 'Modify or Delete' to display it.

Displaying from the Toolbox②
Double-click on the part of 'S/L' or 'T/P' for the position you want to change within the 'Trade Tab' in the Toolbox to display it.

How to Display from the Chart
Double-click on the line indicating the position on the chart, or right-click on the line indicating the position or closing order and select 'Modify' from the menu that appears.

Enter the changes in the displayed position window and click the modify button to complete the changes.
If you want to cancel an already placed closing order, setting the order price to 0 will cancel it.

How to Change on the Chart
When modifying existing positions on the chart, it is necessary to display lines indicating positions and orders on the chart.
Toggle the display of positions and orders on the chart by right-clicking on the chart and selecting 'Trade Levels' from the menu that appears.

You can add or modify a closing limit or stop order by dragging from the line indicating the position to the desired level for placing the closing order.

You can also change the level of an already placed closing order by dragging on it.

If you want to cancel an already placed closing order, right-click on the line indicating the closing order on the chart and select 'Cancel Stop Loss (or Take Profit)'.
