UML diagrams and models (*.uml) can be exported as PDF documents for sharing or publishing purposes. This can be typically done with some kind of UML tool. Just keep in mind that when exported as PDF, the file will no longer be useable as UML format for import.
Convert Visual UML class diagram & model to Adobe Portable document format.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert uml to pdf on Windows
A program used for modeling of UML objects
Convert from uml 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.