Rebate agreement extension issue.

Hi,

We are trying to extend the rebate agreements to period 1 '2014 ( 1st April 2014 to 3rd May'2014) using t.code VB(D, however the same is not getting extended as no entries are available for the same in KONA table. We have already extended the agreement calender to 31st March 2015. The rebate agreement got extended without any problem till 31st March 2014.

PLEASE HELP.

Thanks.