You modify the position of trend lines by repositioning the start or end points, or by moving them to an entirely new position.
NOTE: To modify a trend line in the Chart window, you must display the Chart toolbar. To display the Chart toolbar, right-click the Chart window and select Show Toolbar from the Chart window pop-up menu. Click here for more information.
To modify a trend line, perform the following:
Perform the following to modify a trend line on the Chart Window:
From the Chart
toolbar, click 
NOTE: If you do not see this button, you need to display
the Chart toolbar.
Perform one or more of the following:
To move a single
trend line to a new position, hold the cursor over the trend line until
you the see move
cursor. Click the mouse button and drag
the trend line to a new position, and then release the mouse button.
To move multiple
trend lines to a new position, hold down the CTRL key and then click each
trend line you want to move so that they are selected.
Release the CTRL key. Place the cursor over one of the trend lines until
you the see move
cursor. Click the mouse button and drag
the trend line to a new position, and then release the mouse button.
TIP: You can also select multiple trend lines by clicking and
holding the mouse button while drawing a selection square over the lines
you want to select.