Removing pattern from an object

Hey there,
It's the first time I post here so sorry if I'm in the wrong category.

I'm working on a big project and I'm stuck with this:
I would like to remove the pattern of the pant and would like to know if there's a tool which can "easily" select and replace all the parts looking like this pattern in the picture? Knowing that I won't remove the ligths and shadows since I have to extract it, just need to remove the patterns.

Thank you!