How To resize a Bitlocker partition without unencrypting it

This is a How-To resize a BitLocker (Windows) partition without unencrypting it:

1. Backup the Bitlocker keys
   1. Check the keys with manage-bde -protectors -get C:
2. Shrink other partitions to make some free, unused space
3. Start a WinPE environment
4. Move the partition