|Note: Make sure you are logged-in and in the correct event|
It is possible to update participants by means of a spreadsheet. However the spreadsheet to be uploaded with the new changes needs to have a column with participant's IDs.
Let's take a look at how it's done.
Assuming that your participants have already been uploaded to the event, the first step is to export them to a spreadsheet that will have a column for the participant's codes. To do that, in the "Participant Management" page, click on "upload spreadsheet."
And then download the template with IDs.
Then we need to select the participants that we want to export. These can be grouped in several ways. In the example below, I've chosen to export all participants with registration status "new" because they are the ones for which a I need to make modifications. With the Ctrl key you can select several values. Or you can just choose a different field entirely, such as "participant type" or any other custom field that you have defined in the fields template (only those of the "options" type will show up here and will be available to be selected).
Modify the participants' details in the downloaded spreadsheet and upload it again as you would do with any regular spreadsheet. But do not modify or delete the column of participant's ID! Otherwise you will get duplicated participants.