What you are looking for is a 'center on a date-propert' workflow. With this, you can use a date property on the contact record (e.g. subscription date) to trigger a workflow sending internal and external reminder emails, etc.
What you are looking for is a 'center on a date-propert' workflow. With this, you can use a date property on the contact record (e.g. subscription date) to trigger a workflow sending internal and external reminder emails, etc.