Hello @TonyTrew,
No, this is not possible. As the documentation says: "You cannot edit SAS data sets with the SAS Universal Viewer ..."
Remember that .sas7bdat files (i.e., SAS data sets) are binary files, so "dropping some variables" and creating a new data set from the remaining data is (internally) a fairly complicated task -- too much to ask from a file viewer. You'll need software that (like SAS itself) can create .sas7bdat files.