var x = new GlideMultipleUpdate('sys_user');
x.addQuery('company', "59a8f78c37561304985d8ff1b3990e2f");
x.setValue('company', "d4287b0c37561304985d8ff1b3990e92");
x.setValue('department', null);
x.execute();
var x = new GlideMultipleDelete('service_availability');
x.addQuery('service_offering', "4feb10f237d91b843ecf1f9543990e3a");
x.execute();
Important to note is that dot-walk is not supported. It will just fail silently and update (delete) everything. GlideMultipleDelete will NOT put records into Deleted Records.