how to remove items from json string in c#?

Question

 [

{

"First Name":"John",

"Middle Name":"Rock",

"Last Name":"JohnRock" 

},

{

"First Name":"George",

"Middle Name":"Smith",

"Last Name":"GeorgeSmith"

} 

]

 

how can I remove Last name  from above json

expected 

 

[

{

"First Name":"John",

"Middle Name":"Rock"

},

{

"First Name":"George",

"Middle Name":"Smith"

}

]

Thanks