In recent match opponent used blackwood and in response to partners6diamond she bidsix diamonds which was insufficient a should she call director after dummy noted the error b pass or c she bid nt and as result went down from cold 6 diamonds
a) As with all irregularities the director should be called (I assume 'Dummy' was not yet dummy)
b) The Director will have given the option to pass (if the LHO does not accept the bid)
c) There is no need to make a sufficient bid - pass (but not double) is acceptable
If Pass is chosen (I assume that the player wished to declare in 6D) then play would continue. Their partner would be forced to pass but as this would not damage the opponents the result would be allowed to stand.
Possibly in the circumstances the LHO should accept the 6D and hope that the partner panics and bids on
West opens a Benjamin 2C, North overcalls 2S not noticed by East who bids 2D (insufficient).This was intended as a relay bid and it was not accepted by South. Is a replacement Pass by East now a comparable call? It seems to me that North's 2S has done the relay for the opposition so I would say that Pass shouldn't prevent West from bidding again. Also, exactly what should the director say to East when giving the options?
Director should explain all the options and outcomes below that the offender and LHO have. Then:
a) allow LHO to accept the insufficient bid and let the auction continue - might be quite useful if LHO has a heart suit that they would rather like to tell partner about at the 2 rather than 3 level
b) if the LHO does not accept the bid; allow the offender to pass or make the sufficient bid of their choice. The Director will have explained the consequences of the choice being 'comparable' or not.
Pass would definitely be comparable - but so would any sufficient bid if 2D was a forced relay bid! A forced relay gives absolutely no information about the hand and therefore no unauthorised information to partner (except that the IBer may be half-asleep!) - so no damage. Of course if there were certain hands which wouldn't relay - say hands with a good six card suit - then a sufficent bid over 2S would not be comparable as it would now show a suit not good enough to break the relay.
In this particular example there is no way in which the offender could avoid a penalty by 'making the bid good', ie bidding 3D
If 2D is what responder bids on almost all hands then almost anything is a comparable call because it is more precise than 'almost all hands'.
I don't think there is an answer to 'exactly what should the director say'. It depends on the players: start reading bits of Law 27B1, and explain about comparable calls, and stop when the players look confused; then answer questions (possibly talking to the players away from the table).