Once you've created a custom made activity, you are able to edit it in the Activity Calendar.
As an employee, you will either need to switch to your Personal profile to access your own Activity Calendar, or you go to one of your clients' Activity Calendars.
Once you are in the activity calendar, click on "Add activity" and search for your custom made activity. You could even use the filter for custom made activities to find it. Once you've found it, you can click on it and an "edit" button will appear in your screen.
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