Frequently in this scenario the red will be 100% of either magenta or yellow with 0% black. In these cases you can merely plate the Black & Magenta (or yellow) for press.
I've created a Preflight Fixup on occasion for these also.
An example shown - Note it requires the document is cmyk. MS Files will be rgb. You could create a Preflight looking for rgb colors.
With Fixup tab selected - Options > Create New Fixup > Type of Fixup - search for Spot in the field
