Thanks for the info but I see the information is in C+ and I'm not sure how to code this in Powershell.
This is what I have so far but I'm getting an error in the last line as shown below.
Exception calling "UpdateFileProperties" with "2" argument(s): "1136"
$FileMID=$file.MasterID
$mEcoFile = $vault.ChangeOrderService.GetChangeOrderFilesByFileMasterId($FileMID)
$mEcoNum = $mEcoFile[0].ChangeOrder.Num
$unmappedPropertyName = "Cost"
$propDefs = $vault.PropertyService.GetPropertyDefinitionsByEntityClassId("FILE")
$myProperty = $propDefs | Where-Object {$_.DispName -eq $unmappedPropertyName }
$propInstParamArray = New-Object Autodesk.Connectivity.WebServices.PropInstParamArray
$propInstParamArray.Items += New-Object Autodesk.Connectivity.WebServices.PropInstParam -Property @{PropDefId = $myProperty.Id; Val = $mEcoNum }
$updatedFile = $vault.DocumentService.UpdateFileProperties(@($FileMID), @($propInstParamArray))