Use case:
I have a dashboard Dashboard1. It has a sheet named Sheet 1. Sheet 1 uses a Spice dataset - Dataset 1. I created a copy of sheet 1 with a name as Sheet 2. I created a new Dataset with name as Dataset2 and all the fields in Dataset1 and added a couple more fields.
Problem:
How do I replace dataset1 in Sheet2(which inherited the source as dataset1) with dataset2?
This is not possible currently in the quicksight console.
You either have to replace the dataset or add a dataset and re create the sheet visuals.
You might look into doing this programmatically if you do this often although it might take more time to configure that doing it in the console manually.