Need to change the battery on your Surface Pen? No problem. Follow these steps:
1. Pull the top end straight out from the bottom.
2. Replace the AAAA battery with the positive (+) end of the battery pointing toward the tail end of the pen.
3. Align the flat sides of the pen and push the two parts back together.
For more tips like this, check out the working remotely playlist at www.youtube.com/FoetronAcademy . Also, if you need any further assistance then you can raise a support ticket and get it addressed.