Indesign - how would I merge colours from placed pdf or eps

Hi

In Indesign you have an option to create an ink alias, this means you can choose a colour
and then make an alias of another colour represent it.

What I am attempting to do is do this via applescript, so far using “merge” works fine, only
if the colors are not from a placed pdf, eps etc, this is where the script throws an error

“Adobe InDesign CC 2015 got an error: This color cannot be deleted.”

Manually under “Ink Manager” you can create an alias of the colors from a placed pdf, so I
am thinking I should be able to do it via script, so my question is how would I go about
doing what I am after please?

set destFolder to choose folder with prompt "Please choose folder containing InDesign files"
tell application "Finder"
	try
		set fileList to every file of entire contents of destFolder as alias list
	on error
		set fileList to every file of entire contents of destFolder as alias as list
	end try
end tell
tell application "Adobe InDesign CC 2015"
	repeat with oneFile in fileList
		delay 2
		tell front document
			set New_Colour to swatch "PANTONE 578 U" -- COLOUR IS CREATED IN INDESIGN
			set Old_Colour to swatch "PANTONE 376 C" -- COLOUR IS IN PLACED PDF
			New_Colour merge with Old_Colour
		end tell
	end repeat
end tell

Indesign CC 2015 - OSX 10.11.1

a little more research and it appears that to do what I am wanting I am going about it the wrong way
seems that “alias ink name” is the correct terminology in this instance (seems logical now)

set alias ink name of ink "PANTONE 376 C" to "DO NOT PRINT" as string

works quite well, just got to add it ot a larger script now

tell application "Adobe InDesign CC 2015"
	--activate
	tell active document
		set _NotUSED to {"None", "Paper", "Registration", "Keyline"}
		set _inks to (get name of every ink whose name is not in _NotUSED)
		set _usedinks to (choose from list _inks with multiple selections allowed)
		repeat with _AliasInk in result
		set alias ink name of ink _AliasInk to "DO NOT PRINT" as string
		end repeat
	end tell
end tell