My code:

class hr_employee(osv.osv):

      _inherit = 'hr.employee'

'own_location' : fields.many2one('location.location','Own location'),

'location_line_ids': fields.one2many('employee.location', 'location_line_id', 'Location'),

class employee_location(osv.osv):
      _name='employee.location' 
      _columns={              
                'current_location':fields.char('Current location'),
                'new_location':fields.many2one('location.location','New location'),
                'start_date' : fields.date('Start Date'),
                'end_date' : fields.date('End Date'),    
                'location_line_id':fields.many2one('hr.employee','Employee location',ondelete='cascade'),  
                }  

When i select 'new_location' the value of the new_location will have to updated in the 'own_location' many2one fields.

For eg: when i select 'new_location' field in my one2many field, i want to call a onchange function, in that function i want to update the value of  new_location in the 'own_location' many2one field. Before that i want to clear the existng valiue in 'own_location' many2one field. Then will update the value.

How is it possible?