Experience Cloud is a solution that the Marketing team can consider that will enable former students to update their email address. Experience Cloud allows the college to create a branded online community where former students can log in, view and edit their profile information, and interact with other alumni. Experience Cloud also integrates with Salesforce, so any changes made by the former students in the community will be reflected in their Contact records. Social Studio, Salesforce Engage, and Salesforce Inbox are not solutions that can enable former students to update their email address. Reference:
https://www.salesforce.com/products/experience-cloud/overview/
https://trailhead.salesforce.com/en/content/learn/modules/community_rollout_impl/community_rollout_impl_basics