Modify some distances on a STEP file and save it as STP

Job ID: 33017726

Budget: €30 – €250 EUR

Hello,
we need to change some heights on a STEP file, the problem is , the STEP file only opens with NX unigraphics ( siemens) and it is a big file of 390MB.
Also you need to save the STEP in STP after the modifications are done, and this STP file has universally openable form different softwares.