How do we cancel or reverse Disconnection Document

Hi,

I am new to ISU.

As per the requirement I am going for Re-connection when system receives payments from customer.

I need to do certain validation and actions before actually going for Re-connections such as

if current status is - Disconnection Document open -No Service Order

system status - 1 (New, release unnecessary)

Action - Cancel the Disconnection Documentmet

My Query is : How do I cancel the Disconnection Document ?

Is these any function module / BAPI for this.

Could you provide me the Function module and its required parameters for the same.

Thanks

SKM