Using PACK ON while editing and saving members in a dataset helps us
utilize the space more efficiently. But Packed format is not supported
while processing these members, say for example compiling a cobol program
in packed format may fail.
To save a member in Packed format you can give command line command
and then save the member
To unpack the member you can edit the member and issue command line command
and save it to unpack it.
You can know which format your member is saved in by issuing the command line
which will list various other information including the format in which your member