The freely available LibreOffice still supports old StarOffice formats like the SDA so it is most likely the easiest way how you could manage an SDA to PDF conversion. Some on-line conversion services like ZAMZAR can also probably manage this conversion.
Convert OpenOffice.org drawing file to Adobe Portable document format.
We found one software available in the database for this conversion.
Multiplatform software - convert sda to pdf on any platform
Graphic and diagram software from LibreOffice suite
Convert from sda 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.