yes, you can reset or set to specific value using Dashbaord Extender BR. see "RPTA_SolutionHelper" for examples. something like below:
'*********************************************************************************************************************************************
' PARAMETER COMPONENT SELECTION CHANGED EVENT HANDLERS
'*********************************************************************************************************************************************
Case Is = DashboardExtenderFunctionType.ComponentSelectionChanged
If (args.FunctionName.XFEqualsIgnoreCase("ValidateDatesForRefresh")) Then
Dim taskResult As New XFSelectionChangedTaskResult
taskResult.ModifiedCustomSubstVars.Add("DashboardToHide_RPTA", "9_NoFilterSelected_RPTAV")
taskResult.ModifiedCustomSubstVars.Add("ReportLabelHeight_RPTA", "*")
taskResult.ModifiedCustomSubstVars.Add("FilterLabelHeight_RPTA", "0")
taskResult.ChangeCustomSubstVarsInDashboard = True
Return taskResult