Reg. Reverse of PGI in previous month.

Dear Friends

The below is our client requirement please give a suggestion..

Sales order created for March month

Delivery and PGI done for March month

in delivery they did a mistake

so they reversed the PGI in current period (April) by mistake, instead of March month

but they want to do PGI in March month, stock is available in April month. How to resolve this issue...

Thanks

Rajakumar K