In my example below, I added a new family membership to my account and am going to edit the expiration date.

To access the Audit Log, you can click on the link from a customer's profile page.
​

​
Another way to view it, is to type in the global search box "Audit Log".
​

Change the "View Changes To" the Memberships option. You can choose whether you want to enter in a date range or leave it blank to search all dates.
​