How to eliminate CMYK colors behind pantone channel design without erasing whole CMYK layer?

[maxwell]

I am preparing a file for printing that uses CMYK printing with a metallic ink pantone image over the CMYK. The printing agency requires the CMYK background only underneath the pantone design to be removed while keeping visible the rest of the CMYK layers that are not covered by the pantone image. Is there a simple way of doing this?

For example, imagine the file is a blue square. The blue square is CMYK and I have a red pantone circle as its own channel over the blue square. How can I remove the exact area of blue in the CMYK layer behind the pantone circle? In my actual file the "red circle" is a much more complex image. 

I look forward to hearing your thoughts. Thank you!

[c.pfaffenbichler]

Could you please post screenshots with the pertinent Panels (Toolbar, Layers, Channels, Options Bar, …) visible? 

Load the Spot Channel as a Selection, invert the Selection and create a white Solid Color Layer. 

With Spott Channel areas of other values than 100% this naturally can become pretty nonsensical.

Anti-aliased edges should not be an issue themselves but you may want to employ trapping for the spot color – most likely choking the knock-out for a metallic color:

Best ask the print provider about how much to contract the knock-out. 

[Norman Sanders]

Was there a reason to post this inquiry four times?

[c.pfaffenbichler]

Here is an short explanation of trapping (with regard to CMYK, but the principles can pretty much be applied to Spot Colors). 

https://helpx.adobe.com/photoshop/using/printing-images-commercial-printing-press.html#prepare_an_im...

Edit: 

[NB, colourmanagement net]

I think you'll need to add a mask layer beneath the pantone layer and above the CMYK 

I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer:: co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management