search for a Text in a sentence and then pass the purchase order number to the customer in SAP PO

Hi Experts,

i have to search for a Text in a message (purchase order number)and then pass the purchase order number to the customer in SAP PO

The text received are

Reprocess - Purchase Order Number -12344444

Material 123456

Text 134222

I need only the values of Purchase order number - 12344444.

Regards

Prashant