on neutral territory
In a location or setting to which neither side (e.g., in an argument, competition, etc.) has a connection and therefore gains no benefit or advantage. I find couple's therapy to be helpful because it gives each partner a chance to air their frustrations on neutral territory. The peace deal between the two countries was brokered on neutral territory in the European capital.
on neutral ˈground/ˈterritory
in a place that has no connection with either of the people or sides who are meeting and so does not give an advantage to either of them: We decided to meet on neutral ground.