addressed rephrase from PG-1418

Signed-off-by: Kai Wagner <kai.wagner@percona.com>

contrib/pg_tde/documentation/docs/functions.md

@@ -234,7 +234,7 @@ The `ensure_new_key` parameter instructs the function how to handle a principal
 
 Creates or rotates the default principal key for the server using the specified key provider.
 
-The default key is automatically used as a principal key by any database that doesn't have a specific principal key created the first time an encrypted database object is created.
+The default key is automatically used as a principal key by any database that doesn't have a specific principal key already created when the first encrypted database object is created.
 
 ```
 SELECT pg_tde_set_default_principal_key('name-of-the-principal-key','provider-name','ensure_new_key');