each year's amended return must be prepared separately. make sure you click on file an amended return
you can't move the data. write down what was entered for the various lines on schedule E. if you took depreciation you need to write down the details. Make sure you have everything you need then delete schedule E. enter the info on schedule C. assuming 2018 has been processed by the IRS. you got your refund or the IRS processed your payment, you can file the amended return but only by mail. use a service where you get proof of delivery. send payment if any is due. on the check write the: tax year, your SSN, address, form 1040-x, e-mail address, and telephone number. The IRS will bill you for any penalties and interest. Because the IRS isn't processing mailed-in returns at the moment expect a long wait to hear from them. you would do the same for 2019 but then only if it has been processed. if it hasn't wait until it has. It too can not be e-filed.