At times it is necessary to convert a rounded rectangle into a true vector object.
Perhaps you only want to have one or two corners rounded or perhaps you want to
use the rounded rectangle as a clipping mask.
While not elegant, to perform the conversion, paste the rectangle to a new artboard and
"Save a Copy..." choosing SVG as the file type . Then open the SVG and cut an paste the
SVG object back to the original artboard.
See also
Use your Android as a Chamberlain garage door opener remote