I presume you know all your printers on your printer server? Just create your own array.
I presume the same printers have been created on the new server... I also presume that printer names and printer shares have the same name?
You should not replace the $_Pri. You keep the UDF as it is and add it p.e. at the end of your script.
Here is a script that I did not test!!!
Code:
If NOT @LOGONMODE
	Break On
Else
	Break Off
EndIf
Dim $SO
$SO=SetOption("Explicit", "ON")
$SO=SetOption("NoMacrosInStrings", "ON")
$SO=SetOption("NoVarsInStrings", "ON")
$SO=SetOption("WrapAtEOL", "ON")

Dim $OldServer, $NewServer, $ArrPtrs, $Ptr, $PtrMapState, $NUL
$OldServer = "OldServer"
$NewServer = "NewServer"
$ArrPtrs = Split("Printer1,Printer2,Printer3",",")
For Each $Ptr In $ArrPtrs
	$PtrMapState = $PriMapState("\\" + $OldServer + "\" + $Ptr)
	If 0 < $PtrMapState			
		$NUL = DelPrinterConnection($Ptr)
		If NOT @ERROR
			$NUL = AddPrinterConnection("\\" + $NewServer + "\" $Ptr)
			If 2 = $PtrMapState
				$NUL = SetDefaultPrinter("\\" + $NewServer + "\" $Ptr)
			EndIf
		Else
			? "Error deleting Printer Connection " + $Ptr
			? "Error " + @ERROR + ": " + @SERROR
		EndIf
	EndIf
Next