There are two ways to change the Primary Contact of a Company. My favorite is from the Company Detail Page:
Mouse over the value box of the Primary Contact line (when you mouse over it, it turns gray):
Double click this gray area and it will give you a dropdown of all of your “Other Contacts”… just choose from that list. (If you already have a Primary Contact, that Contact will drop into the Other Contacts area (so, it will switch places with the new Primary Contact)):
Now Jason Alba is the Primary Contact, not an Other Contact. Note, it’s easy to add a new Other Contact or associate an existing Contact.
The other way to do this is to EDIT the Company record. At the bottom of the Company record edit page you’ll see a list of all of the Contacts associated to that Company. Simply choose who should be the Primary Contact, save it, and it will update with that Primary Contact.
(even though I only have one Contact associated to this Company, you get the idea :))
That’s it – two easy ways to change who the Primary Contact is on a Company record.