Maintaining BLEN attribute of DTAB

Is there a way to modify the BLEN values of DTAB other than every time modifying the whole entries using the command similar to BLEN (10 15 20 25).

Is it possible to append a new length(also modify values in between) with out disturbing other entries.

Have you tried with BLEN NUM5 30 ?
Where NUM5 is the 5th entry of the array

Yes, tried that .  but it is giving syntax error

you can use the below command when you want to populated the 5th entry.

ATTRIB BLEN NUM 5 = 30  

you can use the below command when you want to populated from 2nd to 4rd entry.

ATTRIB BLEN NUM 2 TO 4 = 16 21 26

Thanks atish.. this is what i was looking for