To get the partial reconciled account move lines in Odoo v16, you can use the reconciled_line_ids field of the account move line object. This field contains the list of account move lines that have been reconciled with the current line.

Here's an example code snippet that shows how to retrieve the partial reconciled lines for a given account move line:

move_line = self.env['account.move.line'].browse(line_id)
partial_reconciled_lines = move_line.reconciled_line_ids.filtered(lambda l: l.matching_number == 'P')

In this code snippet, line_id is the ID of the account move line you want to retrieve the partial reconciled lines for. The browse method is used to retrieve the account move line record. Then, the reconciled_line_ids field is accessed to get the list of reconciled lines. Finally, the filtered method is used to filter the list and only keep the lines that have a matching_number of 'P', indicating a partial reconciliation.

Once you have the partial reconciled lines, you can use their debit and credit fields to calculate the balance between them and the current line.