You must inherit class pos_details() in your module and add order='date_start asc' clause, like this:

class pos_details(osv.osv_memory):
      _inherit = 'pos.details'
      

def print_report(self, cr, uid, ids, context=None):
 if context is None:
 context = {}
 datas = {'ids': context.get('active_ids', [])}

 res = self.read(cr, uid, ids, ['date_start', 'date_end', 'user_ids'], order='date_start asc', context=context)
# or #  res = self.read(cr, uid, ids, ['date_start', 'date_end', 'user_ids'], order='date_end asc', context=context)

 res = res and res[0] or {}
 datas['form'] = res
 if res.get('id',False):
 datas['ids']=[res['id']]
 return self.pool['report'].get_action(cr, uid, [], 'point_of_sale.report_detailsofsales', data=datas, context=context)