How to reissue an E-mail ID (S/MIME) certificate?

Reissue means issuing a certificate once again while retaining the end date of that certificate. Certificate reissuance through this mechanism is completely free and available for the entire period of certificate validity. This mechanism applies in the following situations:

Loss of a private key,
Mismatch between the certificate and the private key,
Removal of the certificate or key from the server,
Private key exchange,
The owner of a certificate wants to exchange the certificate for a new one for various other reasons.

NOTE — IMPORTANT INFORMATION FOR USERS WANTING TO REISSUE A CERTIFICATE!

Mechanism: Certificate Reissue.

If a certificate Reissue is to be performed, only one, most recent certificate may remain valid. A certificate for which a Reissue has been performed will be automatically revoked 2 weeks after using the certificate Reissue mechanism. This is the time to swap certificates on the server.

Because of this, we encourage all users using the Reissue mechanism to install the reissued certificate immediately, in order to maintain certificate continuity on the website.