Yes but it wasn't by Levi. It was the battle to reclaim Eren,Armin,and Mikasa's home to find the secretes hidden in the basement. That was the first time those spears they carry on their arms were used.
That same battle though before that event happened (Reiner was in Titan form), Armin had them search the walls, Reiner was discovered and it was either Levi or Mikasa ( believe it was Levi though) was able to stab him the neck but he wasn't decapitated and instead transformed.
Yup
But he just placed his sword in his neck, didn't cut it off... TT
Wasn't there a chapter where Reiner (in human form) was almost beheaded by Levi but was able to live because he transferred his conciousness (?) Or something?