Alter existing UV Coords

Hello! Is there a way to edit the uv coordinates of a texture whose UV coords have already been assigned?
6:08 PM] I created this slope mask and I want to make the white area bigger by a very slight offset, I was thinking I could shift the uv coords in 4 or 8 directions and combine them all with max, but I don’t know how. I created the mask using the slope mask function.