For the GetStore call, the value returned in this field indicates the user's eBay Store subscription level.
For the SetStore call, the user can only cancel the current eBay Store subscription (using the Close enumeration value), and cannot change the subscription level. A seller will have to go to the Subscriptions area of My eBay to change their subscription level. Keep in mind that an early termination fee may apply if a user has a yearly subscription, and then either cancels their subscription, or downgrades their subscription level.
See the
Field Index to learn which calls use SubscriptionLevel.