You can void and correct Signed Agreements by changing the status of the Agreements to "Voided." You'll then create a new corrected version of the Agreement Template for Partners to sign and delete the old Template.
Voiding Agreements:
You can set the status of Agreements to "Voided" by going to Partner Management in the left navigation menu > Agreements. You'll then click the checkboxes next to the Signed Agreements that you want to void > Actions > Void Agreement.
You can also void Agreements by going to the "Agreements" tab on the Partner's Page and selecting the checkbox next to the Agreement > Void.
Correcting Signed Agreements:
Once you've voided the Signed Agreements, you can create a new version of the original Agreement Template by going to Settings > Partner Agreements > Partner Agreement Templates. You'll then click on the original Template to view its details > Actions > Duplicate. 
- Update the Title of the Agreement to include "Version 2" or something similar.
- You can also add a description to indicate that it's a corrected version of the original Agreement.
- Scroll down to the Agreement Text section to make your changes and click Save.
You can then delete the previous/original version of the Agreement Template by going to the Template and clicking the Actions button > Delete.
The system will then prompt new and existing Partners to sign the new Agreement Template.
Related Documentation:
- What is the Partner Agreements Functionality and How Do I Use It?
- Partner Agreements
- How Do I Assign/Unassign Partner Agreements?