How to unflag the delete indicator in service PO

Hi Experts

The deletion indicator is set in service line item

The flowing step I have done but it appeared in uneditable mode ( grayed out )

Goto ME22N ->> Put your PO No ->> Goto Item Overview (press F5) ->> Select the main line item and goto Services ->> Select respective service line and check the acct. (pop up will come) ->> click on yellow  coloured arrow. ->>  here check column "D" - Acct  which is flagged .

Please tell how to unflag the delete indicator as it appeared in gray mode  (uneditable  mode) .

Many Thanks !!