transaction key issue

Hi

i have done return order from customerva01.. then i do deliver for return (PGR)... and do the vf01 fro billing ... document has created.. then see the accounting documents..for this billing documents

1 11 100296 M/S. VENKATA SATYANARAYANA KIR 125.00-

2 40 58156000 Other Sales deductio 125.00

here i want to change the G/L account ... this will be post to another G/L account ...whre can ii change this G/L accont insted of 58156000...in SPRO....pls could anyone help me in this issue..

regards

sesidhar