How to reload other document after save?

For example I have this custom script in purchase receipt and I want to update or save certain fields in the purchase order. How to reload purchase order in python?

@frappe.whitelist()
def update_per_receive(data, field):
    data = frappe.parse_json(data)

    if isinstance(data, dict):
        data = [data]

    for d in data:
        if d.get("is_cancelled") == 1:
            po_doc = frappe.get_doc("Purchase Order", d.get("document", ""))

            if d.get("pr_total_qty") == d.get("po_total_qty"):
                po_doc.set(field, 100)
            elif d.get("po_total_qty") > 0:
                po_doc.set(field, (d.get("pr_total_qty") / d.get("po_total_qty")) * 100)
            else:
                po_doc.set(field, 0)

            po_doc.save(ignore_permissions=True)
            #reload purchase order document
            frappe.db.commit()

Hi there,

Can you be more specific about what you are seeing? Where is the purchase order showing stale data?