See the attached upgrade guide for steps on upgrading from RadiantOne FID v7.3 to RadiantOne v7.4.
It is a best practice, and reduces risks, to have a new environment for installing v7.4, and then migrating the configuration from v7.3. Keep the v7.3 environment working as a backup until the new v7.4 environment is installed, tested and ready for production. Once the new environment is ready, switch the client load to it.
Note - an automated upgrade from RadiantOne ICS v7.3 to v7.4 is not supported. Contact your Radiant Logic Account Representative to discuss upgrade assistance.