In Point of Sale, navigate to the Member tab and tap "Select or Register Patron".

Search for the Patron by name, and select them.

The membership history of the patron will be visible on the Overview tab.

Click the "OK" button to proceed.  If the patron has had a membership before, then you will be presented with the option to renew. Select the membership to renew, and tap "Renew selected".

You can optionally change the start date for the membership by tapping "Select start date".

NOTE: Depending on the membership setup in Back Office, the start date for the membership will either default to the day of sale, or the day after the previous membership expires. Be sure to check the date is correct before proceeding.

Tap "Add to transaction" to proceed with the sale.