suppress blank lines

Base Report Builder
How to suppress blank lines
e.g. is there a trick using conditional print expressions

WHY is it not a property

Sorry, don’t understand the question. The whole point surely is that you shouldn’t have blank lines in the data set that you are using for your report ?

Alternatively, use Mailmerge in a Writer document, and there you can set a paragraph property that hides the paragraph where a value of the field inserted into in the paragraph is NULL