Much like any other documents, even latex documents and drawings (such as the .lp files) can be printed or saved as PDF files. This can be typically done with some kind of export function. If there is none, you can always use a virtual PDF printer.
Convert LaTeX drawing file to Adobe Portable document format.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert lp to pdf on Windows
A document preparation system for high-quality typesetting
Convert from lp file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.