If you meant Premium Services, see this support FAQ - https://ttlc.intuit.com/turbotax-support/en-us/help-article/change-service-level/remove-premium-services-bundle/L9umkwOq2_US_en_US?uid=m9emd740
If you meant the Premium online editions, see this to downgrade - https://ttlc.intuit.com/turbotax-support/en-us/help-article/change-service-level/downgrade-lower-priced-version-turbotax-online/L2IDaMvkt_US_en_US?uid=m9emef2p