We can make suitable change of any control property by editing its template. Most effecting thing is style change. You can change your control as you wish. Without editing it is hardly possible to change control as we needed. Suppose we want to change button style or child window cross button it is never possible without editing their template. Expression blend gives facility to edit template. Below are the steps required to change or editing template.
1. Open project in expression blend.
2. Select control to edit.
3. Open Object & Timeline window. Right click on control -> Edit Template -> Edit a copy -> Give a name(Optional) -> Click ok.