Correct values from a BLE_Sensor

How would I correct i.e. the temperature value for a sensor from the ble_monitor integration?

I have added the ble_monitor: statement in the configuration.yaml.

  hci_interface: 0
  discovery: True
  active_scan: False
  report_unknown: False
  batt_entities: True
  rounding: True
  decimals: 1
  period: 60
  log_spikes: False
  use_median: False
  restore_state: True  
    - mac: '4C:65:A8:DD:FF:D3'

How would I i.e. add 1 to the temperatur (state?) value without creating an additional sensor?