Please follow the steps for change item Price from Back-office
Login To Back Office > go to ‘Product’ > click on ‘Bulk upload’. Select shop in the drop-down option of ‘Select Store’ > click on Update’.
After Update. click on ‘Download Item Section and Partner Price’ > open excel File ’ > changes for excel file as per Requirement and Save the file
After Click Update ( Before Uploading the file we should select ‘Upload Type’ as ‘UPDATE_SECTION_AND_PARTNER_PRICING’
Click On Update > click upload type as ‘UPDATE_SECTION_AND_PARTNER_PRICING’ > upload file > save product list.