How to append and swap materials with the same name? Is there a way to swap material with the same name after appending the material from a different file? 

As default, when you have a material named 'Blue' and you append material from another file called also 'Blue', it gets automatically renamed to '0 Blue.001'. Is there a way the new 'Blue' gets simply swapped with the old 'Blue'?

In most cases, the default renaming is obviously desirable, but when you work on several files and you want to change something in one material in all files, you need to go through arduous process of changing that material in every file by appedning and picking it from the list of materials. Any way to automate it?
You should link materials and not append them in mutliple projects, by linking you have the benefit of only updating your master blend file or library and see the changes propagate in all blend files that use that material.  

see also : 
What is the differance between Linked and Appended data from external .blend files?