Update report dataset query for Application Insights metrics

I'm using Power BI Pro in Azure and I've created a report with charts that consume Application Insights metrics (customMetric). In AI then I select Logs, paste in the query, click Run, click Export | Power BI (New dataset) and then create the report.

I want to manually edit the query (For example, Change the 'where' clause) but I can't see where to edit the query. If I create a new dataset instead then I can't see how to update the report to use the new dataset. I have to create a new report each time which is time consuming.

How do I edit the query text and have Power BI pick up the change? Alternatively, how do I change the report to refer to a new dataset that I've created?