If you have purchased a Personal License (which does not allow the design to be used for commercial production/resale items) and you would like to use the design on a commercial product you will can easily upgrade to a Commercial License.
You can upgrade the License of the design through your Patternbank user profile. Go to your profile icon at the top right of the studio page and select 'Transactions' page. Click the 'Upgrade License' button on the relevant design to upgrade your License.