Hi FIZZA,
Thank you for contacting the Microsoft Community.
I appreciate you reaching out to us regarding your scheduled exam. I know how important it is for you to have a smooth experience in rescheduling your exam at your preferred date and time. Rest assured that I will work on this diligently.
For us to further investigate why you are unable to reschedule your exam, kindly provide a step-by-step recording using Problem Steps Recorder (PSR) throughout the entire process, starting from the sign-in page up until the last page that shows you're unable to proceed and send it through the Private message that I initiated along with the information requested. This will help me further investigate as there might be other reasons why you are experiencing an error.
Meanwhile, if urgent assistance is needed with rescheduling your exams, I highly recommend reaching out to Pearson Vue via phone as they have direct access to your exam appointments.
On the other hand, it is correct that as of June 18, merging of profiles is temporarily not available as indicated on this sticky post <Alert: Certification Profile Merging Temporarily Unavailable as of - Training, Certification, and Program Support (microsoft.com)>
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 message. Thank you.
Kind regards,