You can use ASCANDs multi scans and simply select multiple ScanVideos (upright, sideways, etc.) when uploading them to your myascand.xplicator.com account. You will get all individual scan results PLUS a point cloud containing a MERGED version of all files uploaded in your multi-scan. If you like to fine tune the results you can use our browser based multi scan merge editor that gives you a powerful and easy-to-use toolset to align and merge up to 4 scans.
Of course you could also take 2 scans – one upright, one sideways – and combine them through MeshLab, CloudCompare or similar software. YouTube has some useful tutorials on this. This is on meshing, and the second part (starting at minute 10:30) of this is on gluing. Or simply google for “meshlab point based gluing”.