I have seen some sentences, like these, using prepositions before the time delayed.
They put off the event for five days.
But is it okay to leave out 'for' in both the following cases?
I put the appointment off three days.
I put off the appointment three days.
The 'put something off x days' structure doesn't seem wrong to me, because 'off' seems like a preposition, here.
('Put off something' is right, but I know sometimes "put something off" is used, even though something is not pronoun, so I used both forms.)