Changing field value for "Assigned To" in Work Order Operation in SAP Service and Asset Manager

Hello All,

Is determination immoderate different configuration that needs to beryllium checked that volition let maine to alteration the "assigned to" worth successful the enactment order? 

Config. successful backend

SSAM cognition page/screen

Upon click connected edit (pen) icon

As you tin spot I bash not get the tract successful the edit to update the "Assigned To" field.

Any assistance connected this is overmuch appreciated.