Please can u try this
$("table tbody").find($(currentRow)).replaceWith(new_row);
sample code below, please change as per you need.
$(document).on('click', 'span.editrow', function () {
var currentRow=$(this).closest("tr");
var col1=currentRow.find("td:eq(0)").text();
var col2=currentRow.find("td:eq(1)").text();
var col3=currentRow.find("td:eq(2)").text();
$("#name").val(col1);
$("#last_name").val(col2);
$("#email").val(col3);
});
var new_row= "<tr>" +"<td>" +$('#name').val()+ "</td>" +"<td>" + $('#last_name').val()+ "</td>" +"<td>" +$('#email').val()+ "</td>" + "<td>" + "</td>" + "<td>" + "</td>"
+ "<td>"
if(currentRow){
$("table tbody").find($(currentRow)).replaceWith(new_row);
currentRow = null;
}