Hi Rekha,
If you what email address that certification is linked to its best to ask this question at the Certification support forums: https://trainingsupport.microsoft.com/en-us/mcp/forum?sort=LastReplyDate&dir=Desc&tab=All&status=all&mod=&modAge=&advFil=&postedAfter=&postedBefore=&threadType=All&isFilterExpanded=true&page=1
The moderators in that forum can help you with the steps needed to merge you old company account into your new account. Not sure if it will work as you might need access to your previous email account, but I'm sure they know the exact steps of doing this.
Al the best!
Rex