This is a very good but limited offer from Microsoft, to get a second chance to appear for the same exam if you fail.
Its a second shot for you
- Register with any prometric test center of you region/area to appear in the exam
- Take the exam
- Suppose if you fail then show this Voucher to the Prometric center and re-schedule and register for the same exam
For more details follow the link :
http://www.microsoft.com/learning/mcp/offers/secondshot/default.mspx
Good Luck !