Since all our subcontractor don't have access to PP (for confidentiality reasons), it would be usefull to be still able to send them cards.
The simple way would be to email the content of the card in a well formated way. Then when the subcontracor reply on the mail the project manager has a link to close the action if it is done. Of course all mails would be stored in PP card's comments.
The advanced way would be to give access to a secured link / part of the project site where the subcontractor can :