We are planning to add Resolved status whenre in the ticket will be in resolved status and customer can reply back to reopen ticket (Ticket Auto Close). We wanted to add a custom field called Resolved By - which would give the name of the agent who put the status in resolved (Resolved the ticket). I have created the custom field, but wanted to know how to populate this field. What formula/value should i enter here. (Similar to Closed by field)

I am trying to create a validation rule for closing ticket.
The Closure Category (Picklist) and Incident Resolution field must be completed before a ticket can be closed.
I am currently using this formula but its not working for me.
AND(ISPICKVAL(BMCServiceDesk__ClosureCategory__c, ''), $User.BMCServiceDesk__IsStaffUser__c=TRUE && BMCServiceDesk__Status_ID__c ="Resolved" && (ISBLANK(BMCServiceDesk__incidentResolution__c)))
 

I am trying to create a validation rule for closing ticket.
The Closure Category (Picklist) and Incident Resolution field must be completed before a ticket can be closed.
I am currently using this formula but its not working for me.
AND(ISPICKVAL(BMCServiceDesk__ClosureCategory__c, ''), $User.BMCServiceDesk__IsStaffUser__c=TRUE && BMCServiceDesk__Status_ID__c ="Resolved" && (ISBLANK(BMCServiceDesk__incidentResolution__c)))