Hi Prashant,
Once your certification expires, you need to schedule and re-take the exam (AZ-104 in your case).
If you have any questions or need assistance related to certifications/exams/etc., please ask your question in the Microsoft Certification forum using link below. There are support moderators over there that will respond to your question in 1 business day and can assist:
https://trainingsupport.microsoft.com/en-us/newthread?threadtype=Questions&forum=mcp
Please click Accept Answer if above was helpful.
Thanks.
-TP