
Hi JohnJohn0472,
If you set up the alerts for these users and you are a site owner, you can remove the alerts by going to Site Settings and removing the alerts. First, go to Site Settings under the settings cog in the top right corner of the site. Under Site Administration, click on User Alerts. You should see a dropdown for "Display alerts for:"
Click the dropdown and choose the user that you want to remove the alert for and then click Update in order to see their alerts. It should show you all of the alerts they currently have set up for the site. Make sure that the alert that is showing is the one you want to remove. Click in the check box and choose "Delete Selected Alerts". This will delete the alert.
For your follow up question....no, this will not remove the alerts for everyone, just the person you are removing the alert for.
Again, if they have more than one alert set up, you will want to make sure that you are removing the correct one.
Hope this helps!