The Due Date field in the Update Card action in Zapier is a date/time field, but I want to act on the due date removing it entirely from the card or marking as complete. Any ideas?
Try putting "null" as the due date ... although I assume Zapier's date field will not allow that.
If that's true you cannot remove the due date with the native Trello Zapier Integration.
You can do this with a webhook call to Trello however. see https://developers.trello.com/reference/#cardsid-1
The webhook should be a PUT to https://api.trello.com/1/cards/id?key=yourApiKey&token=yourApiToken&due=null&dueComplete=true
You will need to replace id, yourApiKey, and yourApiToken in that URL with the ID of the card, and your API credentials from Trello.
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