Settings can be changed without requiring a technician, but you need to be able to get into the settings as an "installer" to do it. Personally, I think Rainsoft should supply this information to the owner in the owner's manual since they bought it, and it's now theirs. If nothing else, show the info, and tell them they can always call a Rainsoft service center to do it for them if they aren't technical enough to make changes.
To make changes, you may want to plug in an outlet strip with an on/off power switch to the power receptacle, then plug your Rainsoft unit into the outlet strip. Only one setting can be changed at a time, and once the system saves the changes, you will need to turn the power strip back off, and then on again if you need to change more than one setting.
Start by turning off the power strip. Then hold down the Menu < button and the Customer Settings ^ button and while keeping these buttons pressed in, turn the power strip on. When the system boots up it will ask you for a password and you can stop pressing the two buttons. The "password" will be two button presses and it depends on the password chosen by the installer. But, what I found, and others too, is that the password is usually entered by pressing the Customer Settings ^ button twice. Once you do this, you will see that it will now accept changes to menu items.
To enter the installation mode which is where all the settings can be changed, first press the Menu > button which will display "Installer Setup" and then press the Enter button. Once you do this it will take a few seconds and show something like "entering installer setup" where each setting can be changed.
To change a setting you will want to pick which setting you want to change by pressing the Menu > button to go through the list. In your case, keep pressing the Menu > button until you see "Accessory Alarms Setup." Then press the Customer Settings ^ button to change the setting to "Yes" (which means you want to change the accessory alarms settings) and press Enter.
You can look at each alarm type such as Filter and if it shows "On" press the Enter key to change its value and then press the Customer Settings ^ button to change the value to "Off" followed by the Enter key again to save the setting change.
Once you do this the system will save the value you changed and will go back to its normal mode. Unfortunately you can't just change another setting without having to turn off the power strip, hold down the two buttons mentioned above, let it boot up, enter the password (that I indicated above for my case, and probably yours), get back into the "Installer Setup" mode as described above, navigate to Accessory Alarm Settings, find the next alarm type, change its value, save it, etc.
In my case not only did I want to turn off the alarms since I don't even use the filter and carbon tank, but I also needed to increase my water hardness from what the previous owner had set up for his house by the installer. As in everything else, there's a setting for hardness that can be changed as well. I knew what the hardness level was because I had an older system where Rainsoft tested the water hardness and indicated what it was (which was different than the EC4 water hardness setting that I bought on Craig's List).
Once you try these steps you'll be able to change anything in the system, but it will be annoying to turn off the power, hold two buttons down while turning it back on, enter the "password," navigate to the menu item, make changes, then after they are saved restart the whole dopey process again. Unless you only have one thing to change of course.
If you wait too long to make changes once in the Installer Setup mode, the system will revert back to its normal mode.