Hi @JPoppick,
When you navigate to a contact record, you should see a company association on the upper right of the screen:
This is where you can either click Preview and rename the company record or click X, remove the association and associate a new company.
If you’re not working with the company object in HubSpot and simply want to the change the Company name field on the contact record, click View all properties in the left sidebar, search Company name and you can change it.
Hope this helps!