Hi Sumit,
Thank you for contacting the Microsoft Community.
I completely understand how frustrating it must have been to realize the booking error during the exam, especially since you're already certified in DP-600. Allow me to provide you with further information regarding with your concern.
Please note that, according to the current Microsoft Certification Voucher Policy, vouchers are one-time use only and are forfeited if the exam is not rescheduled or canceled at least 24 hours before the scheduled time. This means that once a voucher is redeemed even if the exam is canceled during the session, it cannot be reused or transferred to another exam.
You can refer to the Reschedule and cancellation policies | Microsoft Learn for more information.
Meanwhile, since you have used a voucher in scheduling your DP-600 exam, I highly recommend that you contact the voucher issuer directly. They are the only party authorized to review and potentially reissue or reassign the voucher under exceptional circumstances.
Additionally, you may consider the following below for the other available discount in scheduling your exam:
Company Discount
If you're currently an employee, kindly check with your organization if they're affiliated with Microsoft as Enterprise Skills Initiative (ESI) which can give you company discount for your exam. For questions or inquiries about the company discount policy and benefits, I highly recommend contacting the ESI Support Team using the contact information I provided through private message.
Student Discount
If you are a student, you can take advantage of the academic pricing once you complete the interest survey and by following the steps for Student discount. Once done, you will be eligible of 45% discount and all role-based Exam (except India and China), and a 30% discount for Fundamentals exam (all countries). Please note that the student discount will be automatically applied at checkout page.
For your future reference, you can also check the Microsoft Blog and Microsoft Events Catalog for announcements of upcoming events that offer discounts for exam.
Thank you for your understanding.
I look forward to your response. Please note that if no response is received after two business days, the case will be closed and locked. After the case is locked, we will no longer be able to respond, even through Private Messages.
Best regards,