To convert 'James will repair the car' to passive voice, it becomes 'The car will be repaired by James.'
To change the sentence 'James will repair the car' to passive voice, one must rearrange the sentence so that the subject is not the doer of the action, but instead is being acted upon.
In passive voice constructions, the object of the active sentence becomes the subject of the passive sentence.
This change involves using a form of the verb 'to be' along with the past participle of the main verb.
Following these rules, the sentence in passive voice would be: 'The car will be repaired by James.'