Quad Problem deleting edge?

Quad Problem deleting edge?

I have a polygon object I want to turn it into a quad instead of tri,
When I delete the edge it doesn't work right.
I'm thinking it should turn to a quad but it doesn't.
Any idea why.
Thank you

This is correct as you´re deleting the upper right point as well and the polygon will collapse to its remaining anchor points.
In situation you can use insert point at the diagonal edge and weld-to-first point to make these 2 tris one quad like so:

Cheers
Frank

Many Thanks you are the Man!