Typically, a patch can be installed over the top of an existing program, but again this will depend on the supplier and the nature of the patch. (The software patch)

A Critical Patch Update is a collection of patches for multiple security vulnerabilities. (Oracle Technology Network)

All this is achieved through a single console with extensive reporting functionality, effectively addressing the three pillars of vulnerability management: security scanning, patch management and network auditing. (WindowSecurity.com)