Any document or graphics file can be easily exported and saved as PDF document with the help of virtual PDF printer, provided you find a tool that can open / view / print your file.
In case of .sds files, which are typically charts from OpenOffice, you probably just need to download the software (or its alternatives), open up the chart in spreadsheet or drawing editor and simply print it out as PDF.
Several different .sds file type exists, so perhaps another kind of this conversion is doable as well, but in any case, using virtual PDF option is the way to go.
Updated: November 2, 2023