How to suspend BitLocker protection
Open the control panel, then click BitLocker Drive Encryption
Click "Suspend Protection"
Click "Yes" when the dialog box prompts whether you would like to suspend BitLocker Drive Encryption.
The BitLocker Drive Encryption should now list its status as "Suspended" with a yellow exclamation point over the drive logo.
How to save a copy of the BitLocker Recovery Key
Open the BitLocker Drive Encryption control panel and click "Manage BitLocker."
Click "Save or print recovery key again."
Click "Save the recovery key to a file" and make sure to save the recovery key to either a network share or a USB drive (you will get an error message if you try to save to an encrypted drive).
Once you've saved the recovery key to the desired location, click "Close" on the Manage BitLocker window.
How to resume BitLocker protection
Open the BitLocker Drive Encryption control panel and click "Resume Protection."
The yellow exclamation mark over the hard drive should disappear and a padlock icon should now appear over the hard drive in the BitLocker Drive Encryption control panel.