In English, an active sentence is turned into a passive one (also known as the passive voice) as follows:
The cat has eaten the mouse. → The mouse has been eaten by the cat.
The passive voice can be used both in simple tenses, i.e I go, I went, I will go, and compound tenses, i.e I have gone, I had gone.
To learn how to form the passive with simple tenses see Forming the passive voice with ser + participle (+ por) (passive - simple tenses).
Take a look at passive sentences in Spanish, conjugated in compound tenses:
As you can see, the passive voice is formed by verb ser conjugated in a compound tense and a participle.
Note that the past participle agrees with the subject of the auxiliary ser:
platos → lavados
nosotros → condenados
manzanas → horneadas
candidatos → elegidos
In order to turn a sentence from active to passive voice, the tense of the auxiliary ser must be the same as the tense of the main verb of the active sentence. For example:
El cliente ha rellenado el documento. → El documento ha sido rellenado por el cliente. (present perfect tense)
El cliente había rellenado el documento. → El documento había sido rellenado por el cliente. (pluperfect tense)
El cliente habrá rellenado el documento. → El documento habrá sido rellenado por el cliente. (perfect future tense)
El cliente habría rellenado el documento. → El documento habría sido rellenado por el cliente. (perfect conditional tense)
Notice that, just like in English, the pattern is as follows:
- The object becomes the subject.
- We use the auxiliary verb ser (not estar) in one of the compound tenses, followed by the past participle of the verb.
- We use the preposition por to introduce the complement.