Burn a fresh copy of NOOBS lite 2.7 to a SDCard.
Copy everything in partition #1 (/dev/sda1) on the new SDCard to partition #1 (/dev/mmcblk0p1) on the old NOOBS system EXCEPT recovery.cmdline.
If you copy recovery.cmdline you WILL trash your system.
Cross fingers, stick two pencils up your nose, turn round three times, say "Wibble" and hope you've not screwed the old NOOBS card. Reboot.
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