hi,
You can replace the certificate, withot trouble, but, you need to stop the migration before to change or replace the certificates, and then you can continue migration, from on-prem to VMC and viceversa
Please consider marking this answer "correct" or "helpful" if you think your question have been answered correctly.
Rolando Kohl
https://www.linkedin.com/in/rmkohl/
Rolando Kohl
VMware Certified Instructor - Cloud Architect - Argetina VMUG Leader - vExpert 2014 - 2024
vExpertPRO
VMware Instructor VMware IT Academy
https://www.linkedin.com/in/rmkohl/