Expanding Brush Strokes
You can use the function Expand Stroke to convert brush strokes into an ordinary object. The original path will be a separate object. Note that the way you can edit the object changes with the conversion. For example, if the original object was a curved line with a specific stroke width, you will not be able to reshape the object by changing the stroke width anymore. On the other hand, you will be able to adjust individual segments or anchor points of the expanded object.
How to expand brush strokes
1. Select the stroke(s) you want to expand.
2. Choose Extra > Expand Stroke.
The selected brush strokes are separated into an ordinary object and the original path (not shown in the following illustration).