Assign one Mnf. item to multiple operations

Hi,

where can I set to be able to assign one manufacturing item (MBOM item) to multiple operations in process planning app? Currently it is not possible, as I try to assign same mnf. item to a second operation, first assignment to first operation has disappeared. But I saw in many videos that it is possible to assign one mnf.item to more than one operations.

I am using 2019x.

Thank you.