Go to Service Administration->Certs Service->Manage certificates. The script provides a menu to select the certificate and the its operations. Choose the certificate (1), like webserver or mailserver. Choose option 11 to renew the certificate request. Follow the screen output. Select 12 to sign the request with the CA certificate. Choose option 14 to create a new certificate and to copy it on the right place. Restart your webserver or mailserver process (/etc/init.d/).
If you have one certificate for multiple namebased hosts on your webserver, you shouldn’t select option 12. Instead follow the instructions on this blog entry: .