You can change multiple Cards' Categories at once on the Project Library, or wherever bulk actions are available (ie Lists, Rundowns, Boards, Kanbans).
Change Cards' Categories on the Library
Click the bookcase icon on the far left of your screen to access the Project Library.
Select the "Cards" tab.
Click "Advanced Search" in the top-right to expand your filtering options.
Filter your search by card category, fields, or a keyword.
Once you have the filtered to the relevant Cards, select their checkboxes, and the bulk actions menu will open on the right.
Click the "Change Card Category" button in the bulk actions menu.
The "Update Card Category" dialog will open.
Select the Category you are changing the Cards to.
Note, if there are fields on the Cards that are not on the destination Category, you will see a warning message in red about what data (fields) you will lose if you proceed.
If you are happy to lose this data and change the Category, click "Save" and then "Confirm".
OR
If you want to change the Category but do not want to lose the data, you will need to add the missing fields to the destination Category BEFORE making this change. See "How do I edit a Card Category's name, colour or fields?" for easy steps.
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