How to replace multiple paragraph markers

The doc i’m editing has 4 blank paragraphs between lines of text. I want to use “Find and Replace” to search for 4 successive paragraph markers and replace with 1 but typing in “^$^$^$^$” returns “search key not found”. Tried it again with “^p^p” (only 2 in a row, as a test)still nothing. TIA.

“Alternative dialog Find & Replace for Writer” works very nicely for just this sort of task:

Also, for empty paragraphs search for ^$ and leave replace empty.