Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide

Using the REWRITE or DELETE statements

REWRITE statements, with or without the KEY option, are allowed for UPDATE files. If you use the KEY option, the record that is rewritten is the record with the relative record number you specify; otherwise, it is the record that was accessed by the previous READ statement.

You can also use DELETE statements, with or without the KEY option, to delete records from the data set.

Rational Developer for System z
PL/I for Windows, Version 8.0, Programming Guide