prepositional phrases - Zero article after "of" in "a change of place"

Given the sentence

The use of apples instead of pears is unexpected in the dish.

I don't think we can use apple instead of apples. (Correct me if I'm wrong.) But then, how come we can say the following?

• I need a change of hotel.


• A change of situation will give another result.

In the above two cases, both hotel and situation are countable nouns. Why is the indefinite article omitted before them?