If you created a sale and applied it to the collection but want to exclude the product from the sale while keeping it in the collection - you may edit the product price manually in the Store admin and set the price you want it to have. The product will appear in the Price Conflicts section of the EasySale app. Here, you may select the "Exclude from sale" option.
Or you may add the products one by one to the sale and avoid adding the ones that shouldn't be on sale. In this case, you'll see the exact list of products to which the sale was applied.