Making Approval / Rejection note Mandatory while Rejecting a Shopping Cart

Hi Experts,

My requirement is to make Rejection Note Mandatory when a approver rejects a Shopping Cart.

I have created an enhancement in CHANGE_DOCUMENT method of /SAPSRM/CL_PDO_BO_SC_ADV class.

Inside the enhancement i have checked if there is a line item in longtext with text_id = 'NOTM'.

Now the problem is, when a approver rejects for the first time without entering comment, it works fine.

But when requester again modifies SC and re-orders it, internal table longtext still holds previous rejection comment. Therefore, the error message is not coming this time.

Suggest me how can i fix this please.

Regards,

Parthi