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Once their account has been enabled, tick the checkbox for that person again, and select the 'change passwords' option from the 'with the selected rows...' dropdown box, and follow the prompts to send login details to that person's specified email address.
From the 'Users and Permissions' page, you can also allow/deny people access to additional areas of the system, such as the ability to add events. For more information on permissions, see this page.
Updating your own information
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