How do i call SetVertexUV?

I’m getting into working with mesh structure.Sorry if question is noobish, but how do I call SetVertexUV?It requires FVector2D as a third parametr, and it modified as constant, while function itself is non-constant.Compiler rejects whatever i try,and it looks for me like nothing will change while parametr is const-modified.
Btw, here’s an error: GetVertexUV and SetVertexUV have same descriptions.
I’d also be pleased for any guides on working with mesh structure.