Aug 4 (Reuters) - Cominar Reit CUF_u.TO
* Cominar updates its unsecured debenture refinancing plan
* Cominar reit - downward changes to credit rating will have negative impact on co's ability to finance in unsecured debt marketplace
* Cominar reit - terms and conditions of outstanding debentures remain unaffected by rating change
* Cominar reit - dbrs said it had downgraded rating of reit's senior unsecured debentures to bb with a stable trend from bbb (low) with a negative trend