Adobe Acrobat XI, version 11.0.10
Left click on any part of the callout. That highlights the lines and grips.
Do not hover over lines or grips, move the mouse over the text.
A 'T' in a square appears next to the courser (tool tip).
Left click over the text. You have now grabbed the text box.
Press and hold the left mouse button to grab and move the text box up and down. While you are doing this the arrow point says in place and the leader changes its anchor point on the textbox to the left, right, top or bottom of the textbox.