Regularly appeal to both province and central commissariats, accepting as legal whichever decision is more beneficial. 

本句为祈使句，隐含的主语为 you.

accepting as legal whichever decision is more beneficial 为现在分词短语作伴随状语。accepting的逻辑主语为听话人you. as legal为宾补，whichever decision is more beneficial为名词性关系分句作宾语。由于宾语较长，故移到了宾补之后，这种现象称为宾语后移。whichever为融合型关系限定词。whichever decision= any decision that.