Edit card details

When you need to update details in a card, is it better to edit the whole card or just the individual field that needs changing?

After prototyping it seems that editing the whole card is more straightforward. Changing the state of the card into edit mode creates a single change of state, rather than individual changes of state for each field - this change feels easier to grasp. It also has the benefit of a single action for users to take and the added utility for users that need to change info in more than one field.