No. (https://www.sfml-dev.org/documentation/2.4.2/classsf_1_1VertexArray.php)
However, there are solutions:
1)
copy all the vertices to the right (assuming the left is the beginning and the right is the end) of the one you want to remove to the one to its left and then resize so that it is one smaller.
2)
use a vector (http://www.cplusplus.com/reference/vector/vector/) of vertices instead of an sf::VertexArray. Remember that you may also need to store the primitive type. You can then, of course, use a vector's erase (http://www.cplusplus.com/reference/vector/vector/erase/) method to remove an element.
e.g. (assumes a drawable class set-up)
// storage
sf::PrimitiveType m_primitiveType;
std::vector<sf::Vertex> m_vertices;
// in draw method
target.draw(m_vertices.data(), m_vertices.size(), m_primitiveType, renderStates);
// erase
m_vertices.erase(m_vertices.begin() + 2);
EDIT: corrected mistake (wrote sf::VectorArray instead of sf::VertexArray)