I have two contacts that changed their emails. In order to have the correct email address auto pop, I deleted the first contact, but before deleting the second, I wondered if, once deleted, does that delete all previous emails from that contact?
In Gmail, deleting a contact from the contact manager doesn't delete the messages received from that contact.
Contacts are stored in a separate area from messages.
You can access the Google Contact manager from the Gmail web UI but also from https://contacts.google.com.