This console command sets the relationship rank between your targeted NPC and the specified reference ID.
setrelationshiprank [reference id] [relationship rank] Target Command
|Reference ID||The reference ID of the NPC you wish to change the relationship of (relationship between this reference ID and your current target).|
|Relationship Rank||A number between -4 and 4:|
setrelationshiprank 0078783 1
The above command would set the relationship rank between your targeted NPC and the NPC with reference ID 0078783 to 1 (friend).
setrelationshiprank player -3
This console command would make the relationship rank between your character (player) and your current target -3 (enemy).