There are various reasons to remove certificates from a certificate store. The reasons include, but are not limited to:
a certificate user has left employment of the financial institution
a certificate has expired
a certificate was installed under the wrong network log-in credentials
a certificate is renewed before the expiration date
When valid (non-expired) certificates are removed, please ensure that your Local Security Administrator (LSA) has received notification to Revoke the certificate as well. This is critical, as it is possible that a certificate may have been exported and may be installed in other locations. Revocation by your LSA will render the certificate unusable regardless of where it is installed.
To remove a certificate from Certificate Manager, simply select the certificate and click the Remove button. Figure 1 below shows a screen where the certificate for user "Cert Tester" will be removed.
Figure 1
Upon clicking Remove, you will be prompted to confirm the action. Click the Yes button and the certificate will be removed.