Save time when updating filters in response to changing reporting needs. You can now change the field in a Lightning report filter without deleting the filter and adding a new one. For example, you can change a filter on Industry to a filter on Type in a report on accounts without having to remove and recreate the filter and filter logic. In earlier releases, you could change the operator and value but not the field. Previously, this feature was available only in Salesforce Classic.
Where: This change applies to Lightning Experience in Group, Essentials, Professional, Enterprise, Performance, Unlimited, and Developer editions.
How: In the Filter By window, change the field, operator, or value.
Easily Update Fields in Lightning Report Filters (salesforce.com)