Find... finding but not Replacing (formatting characters)

Trying to clean up a document by executing a search to "Find and Replace" double carriage returns.

I've tried by highlighting the characters and using "Use selection for..." find/replace, in Edit>Find>. Doesn't work.

Appropriate characters (\n\n, and \n) appear in the Find/Replace window, and Find (sometimes) searches the document to tell me how many offending occurrences there are, but all the action buttons are greyed out and accept no input (mouse click).

I have also tried simply entering the characters directly into the fields, but no luck there either.

HELP! It takes WAY too long to manually pull things like this out!

Pages 11(7030.0.94)

Big Sur 11.2.3

iMac 27" (2020)

i7, 32/512, Radeon Pro 5500XT (8GB)

Thanks Much

SDLeary