Open your Expression Blend and drag a textblock onto the designer. Write some text and increase its font as shown in the picture.
Right click on your text and click on “ Convert to Path," inside of Path, see the picture below.
Your image has been converted to a vector image. In order to see your path image select the pen tool from toolbox as shown below.
You can change the layout of your text by selecting the Direct selection tool from toolbox. See the word “D” in the below picture, by selecting any of its node using the direct selection tool you can change its layout.