Future in the Past is used to express the idea that in the past you thought something would happen in the future.
There are different ways of expressing “future in the past”:
Example: “I was going to go the party, but unfortunately my colleague got ill and I had to do her job.” (I was going to but I didn’t.)
. By using “past continuous”
Just as “the present continuous tense” is used for arrangements, the “past continuous” tense can be used to express what was a future arrangement in the past. (The event may or may not have taken place )
I was travelling to Edinburgh that night, but my flight was cancelled.
. By using “would” , you imply a possibility or expectation, but no plans.
“I knew Mary would win the competition. She was head and shoulders above the rest of the performers.”
a)“was/were to+ inf” (for events which took place)
b) “was/were to have + past participle” (for events which didn’t happen)
“When she first auditioned the judges knew she was to become a great singer.” (the event happened)
“The board of directors was to have promoted Joan as manager, but they later discovered she had been passing vital information to the competition.” (the event was arranged but did not happen)