Replacing colors is a very simple task because we often need to use it. You have three ways to replace colors in the document swatch:
In Edit | Colors, click on the Delete button. You'll need to choose which color will be applied to the object having the deleted color.
But you can also use the Replace Colors window as shown in the next screenshot.
Create a document and import a vector file or logo, which can be the sample ColorShade.svg file or the logo used in Chapter 2.
Go to Edit | Replace Colors where you will be able to define several replacements at once that Scribus will make just after you validate.
Click on the Add button to display a new window that will let you choose the color you want to replace (Scribus shows only used colors): here we have chosen the CustomBlue color.
Don't forget to mention which color will replace it, and which color you want to be applied to the objects; here we changed it to red.