Shape to Stroke

Maha,

You can work on a copy on top of the locked original as follows:

1) Hide the original;

2) Cut the copy at the spot where you wish the new stroke to end at the lower left (the J part);

3) Deselect, then with the Direct Selection Tool Click the end segment at the bottom of the D part;

Now you have two open paths to work with;

3) Click one of the end Anchor Points at the bottom of the D with the Pen Tool, then press P, then Click the other end Anchor Point, and switch to the (normal) Selection Tool;

4) Object>Blend>Blend Options, set the Spacing to Specified Steps: 1 and set the Orientation to Align to Path;

5) Select the open paths from 3) and Object>Blend>Make;

6) Object>Blend>Expand;

This ought to give you a stroke that works most of the way;

6) Adjust the end bit of the new stroke at the J part where it departs from a clean soft bend, using as few Anchor Points as possible, working with positions and Handle lengths/directions.

You can give it a try and show your progress/issues, still using the Insert Photos button which appears directly in your post.