To begin a bulk update of a contract field, navigate to your Contacts tab within the Renewals section and click the check-boxes to the left of each Contract to be adjusted:

Once selected, the Search and Export functions at the top-right of your list will transform temporarily into buttons affording the ability to Edit the selected contracts, or delete them entirely:

Clicking Edit will display the field adjustment dialogue box where you can define the data to be changed and the field's new value:

Once satisfied, click the Update button to apply your changes: