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I'm not sure I understand what VWAP is in the context of VIX or any other stock index, as stock indices are not traded on an exchange. There's no trade price and no trade volume associated with an index value.
For stocks you can retrieve VWAP calculated by Refinitiv between two points in time using TR.VWAP field in =TR function in Eikon Excel, e.g.
=TR("IBM.N","TR.VWAP","StartTime=2020-12-07T10.00.00 EndTime=2020-12-07T10.10.00")