Quick Question-Texture replacement

[Avantyr]

Hello, 
I wanted to know how to replace a texture/ normal map with a bigger more detailed one.
For example I have the R0r0n0's adamantium aion armor and the helmet is 256x256 px, If I place a 512x512 .dds with the same filename in the folder, would the game adapt it correctly or do I have to take some additional steps?
Thanks