To renew an SSL server certificate, navigate to the Server Certificates repository at Repository | Certificates | Server Certificates

Find the certificate to be renewed and select "Renew" from its context menu:

This will create a new Certificate Signing Request (CSR)

Fill in the CSR Form

Click SAVE

A new CSR has been created. 

Next, to get the new certificate, you need to follow the steps below to complete the CSR