To update transactions and related share certificates, navigate to the entity whose transaction you want to update.
Once you are in the entity's profile, select the Securities tab from the lefthand side of the screen and then select Shares as shown below.
Once you're in the Transactions tab, click on the transaction record you wish to modify. In the new window that pops up, scroll down to the bottom and check off Administrative Edit and then click Update.
Navigate to the Certificates tab and you will notice a yellow dot at the beginning of the record indicating that the certificate needs to be modified.
Click into the certificate and go into the Certificate # field to modify the certificate number. Once you've made the change, select Update. You will next need to click Repair at the far right of the certificate record and Validate next to Registers/Ledgers.