If Was If Were ...

We use were when the subjunctive mood needs to be expressed. But was does NOT become were when there is a possibility that the contrary has happened.

• If Joanne were going, I would see the movie. (I know Joanne is not going).
• I would have walked if the bar were nearby. (The bar is far away).
• He would have donated money if he were earning. (He lost his job).

Was remains was:

• If it was a silver BMW, it could be Byron's. (It might be Byron's).
  
• If the war was for oil, it was unfortunate. (Oil may have been a factor for fighting the war).