Hi,
Please, check if note 2054130 - FM_REVALUATION_PO : New exchange rate is not used for revaluation is applicable to you.
If this is not the case, check if you have enough budget to cover these revaluations. For more info, you can consult note 1927811 - Amounts are not displayed in the output list of FM_REVALUATION_PO
Regards,
Eli