Hi,
You only have to add the column to the expression nad make sure you do not check the “Convert to Int” option.
That’s it.
Best,
Armin
P.S. If you have multiple columns to convert, you can use “Math Formula (Multi Column)” node, select all the integer columns you want to convert to double and use $$CURRENT_COLUMN$$ as the expression instead of the column names as used in “Math Formula” node.