Unmerge Vertex with Mirror Modifier On (Make Two Vertices from One at the Center?) I'm trying to model a collar on a shirt, and I'm using the Mirror modifier. I have one vertex at the center; is there any way to "unmerge" it and create two vertices (for the points on the collar)?

 

I know there are other ways to get the effect I want (Knife tool and then deleting the vertex at the center) but I'm just curious to know if this is a feature.
If I understand correctly what it is you are trying to do then all you need to do is temporarily uncheck the Clipping option in the Mirror Modifier menu Then you will be able to select that vertice and drag it away from the center line.