Answer:
<u>Basic Rules for Voices:</u>
1) The tense will not be changes EVER.
2) Interchanging of subject and object.
<u>Now, The changing of Voice:</u>
1) Someone signed a new contract. (Past Simple tense)
2) Her sister walked Julie's Dog. (Past Simple tense)
Hope this helped!
<h3>~AH1807</h3>