*Note* - Code signing new enterprise apps or enterprise app updates for distribution will not work until both are restored.
*Note* - The enterprise distribution certificate can be downloaded from the 'Member Center' located here. However, its associated private key only exists on the Mac and OS X user account keychain from which the distribution certificate was either originally created or to which it had been transferred.
*Note* - Revoking an enterprise distribution certificate invalidates all apps that were signed and deployed with that certificate.
*Note* - A second distribution certificate can be created half way through the validity period of the first distribution certificate. The two distribution certificates maintain oscillating validity which allows for the deployment of a new version of the app signed with the alternate certificate sometime before expiration of the other.
*Note* - Once a working distribution code signing configuration has been restored, a backup should be created to more easily recover from this situation in the future. This can be backed up by following the process laid out in 'App Distribution Guide > Maintaining Your Signing Identities and Certificates > Exporting and Importing Certificates and Profiles' which is located here.
Option 1:
Transfer the certificate from the OS X user account in which the certificate was originally created. This can be performed by using the steps list in Apple's 'App Distribution Guide > Maintaining Your Signing Identities and Certificates > Exporting and Importing Certificates and Profiles' located here. Doing this re-enables distribution code signing without disturbing any currently deployed enterprise apps.
Option 2:
If the certificate for transferring cannot be located, a new one will need to be created. There are two options for creating new enterprise distribution certificates. They are as follows:
The following answers brought forth in this article were derived from the following source:
https://developer.apple.com/library/ios/qa/qa1868/_index.html