To move annotations and dimensions on a drawing, or PMI elements in a model, you can drag them. To reattach them, use Alt+drag.
Select a dimension or annotation you want to reattach or move.
Drag the dimension line handle point(s) to the desired parent object(s). You can change the result by doing any of the following:
To reattach the dimension or annotation, hold the Alt key as you drag the dimension line handle point(s).
To change the dimension value, drag the dimension line handle point.
To maintain a driving dimension value (and therefore modify a feature, for example), hold Ctrl+Alt as you drag the dimension line handle point.
Tip:
You can choose new parents for a dimension or annotation, as well as repair detached or partially detached elements.
When you select a dimension or annotation, its parent geometry highlights.
Partially or fully detached dimensions are displayed in the dimension error color. The connected projection line is displayed in its default color.
When you reattach or replace a dimension, any prefixes, tolerances, and other formatting on the old dimension are applied to the new dimension.
To learn other techniques for manipulating PMI elements, see Move PMI elements.
In the Draft environment, you can use the Attach Dimension command to reattach detached dimensions or to move dimensions to new parents.
In the draft document, choose the Home tab→Dimension group→Attach Dimension command 
.
Click the dimension you want to reattach or move.
Click the element where you want to attach or move it.
Tip:
You can use the Attach Dimension command to repair detached dimensions or to replace any dimension with a new dimension of the same type. For example, you can use this command to replace a dimension on an arc with a new dimension on another arc, but not to a line.
When you use this command to reattach or replace a dimension; any prefixes, tolerances, and other formatting on the old dimension are applied to the new dimension.