How can i update colors blue in red

Working with Data
1 
"_id" : ObjectId("624c73faea32709bef90a948"),
"order" : "03",
"year" : "2018",
"paid" : "N",
"cost" : {
	"price" : 33,
	"currency" : "EUR"
},
"items" : [
	{
		"product" : "p3",
		***"colors" : [***

*** “blue”,***
*** “black”***
],
“quantity” : 4,
“colors[1]” : “red”
}
],
“delivery_days” : 4