Hi Robert
If you are on a dual stack system, you can refer to the following guide on alert configuration
Alert Configuration – Step by Step Guide
Basically, you need to find out which alert category that was used in your system, and then go to t-code ALRTCATDEF, and change the Long & Short Text definition for it.
Below is also another SAP library reference for alert configuration.
https://help.sap.com/saphelp_nwpi71/helpdata/en/80/942f3ffed33d67e10000000a114084/content.htm
Rgds
Eng Swee