You can silently uninstall GeoEvent Server by running the msiexec.exe command.
- Open a command prompt.
- Execute one of the following commands to uninstall your version of ArcGIS GeoEvent Server:
10.6.1
msiexec /x {D0586C08-E589-4942-BC9B-E83B2E8B95C2} /qb
10.6
msiexec /x {723742C8-6633-4C85-87AC-503507FE222B} /qb