Question

passive voice of let us go​

Answer 1

We should go.........

Answer 2

if Jack has said, "Let me go", you might later tell someone: "Jack told the police TO LET HIM GO." This is the normal way to change an imperative to reported speech: imperative ==> infinitive with "to". Or you could say, "Jack told the police (that) THEY SHOULD LET HIM GO."