A common question we receive is:
"I have a supporter with an inactive Email Status (screenshot below). How can I reactivate it so that the supporter receives email again?"
You can definitely reset their Email Status, called the "Receive Email" field, in their supporter profile, to active/subscribed again (location shown below):
...BUT only if they are in full agreement that they wish to be re-subscribed. This is an important policy because re-subscribing a user that does not wish to be subscribed would technically constitute as spam.