This TurboTax FAQ shows what is allowed for a TurboTax Online Free return: https://turbotax.community.intuit.ca/turbotax-support/en-ca/help-article/compare-products/file-free-using-turbotax/L5nEZKBBo_CA_en_CA
You may not be able to delete what is causing your return to be upgraded, as it could be on a T-Slip or transferred from your return from last year (if that is how you started your return).