Sentence:  They who thought they could never be secure in any peace, except the King were first at their mercy, and so obliged to accept the conditions they would give him, were willing to change the <WSD>hand</WSD> in carrying on the war; and many, who thought the Earl of Essex behaved himself too imperiously, were willing to have the command in one who was more their equal. 
Meaning of the word marked with <WSD> tags:  Actual performance; deed; act; workmanship; agency; hence, manner of performance.