diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index 6dd518752c0..ff7071bef5b 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -1206,7 +1206,8 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
        <listitem>
         <para>
          For range-partitioned tables, the ranges of merged partitions
-         must be adjacent in order to be merged.
+         must be adjacent; this applies even if the partitioned table
+         has no default partition.
          The partition bounds of merged partitions are combined to form the new partition bound for
          <replaceable class="parameter">partition_name</replaceable>.
         </para>