Need Transfer only the last Date.

I'm trying to modify this script so that it only transfer the last of the three Rev Date.

In this example it transfers doc with Rev B, not transfer Rev A, or is I have Rev 0 no transfer neither Rev A, Rev B

let signIn := this;
let reply := dialog(" Documento a  Transferir", " Se Transferira el Documento ?", ["Confirmar", "No Confirmar"]);
if reply = "Confirmar" then
    let newRecord := (create Revisiones);
    newRecord.(CodDoc := signIn.text(CodDoc));
    newRecord.(Documento := signIn.Documento);
    newRecord.(Disciplina := signIn.Disciplina);
    newRecord.('Rev A' := signIn.'Rev A');
    newRecord.('Rev B' := signIn.'Rev B');
    newRecord.('Rev 0' := signIn.'Rev 0');
    alert("Documento  Transferido");
    openRecord(newRecord)
end