South was Dealer but her partner (North) put down 'Pass' before anyone else had bid. What happens now?
The first thing the TD should state is that the left-hand opponent of the offending Pass (ie East) is entitled to accept the pass. If they do so, the auction proceeds normally from there and there can be no further TD intervention. East will need to know the alternatives if they don't accept the Pass (see below), but many players miss an opportunity in this situation. Suppose East has a good weak 2♥ opening bid. If they allow North's pass to be retracted, and the auction proceeds, say 1♣ (South), 3♣ (North), then East may now be stuck to show their hand.
If East does not accept the Pass, the bid is withdrawn and South can make any legal bid. North can now bid but it must be a 'comparable bid' otherwise their partner (South) could not bid at her next turn. The phrase comparable bid is a tricky one and is defined in Law 23A2 as when it 'defines a subset of the possible meanings attributable to the withdrawn call'. In reality this means any bid that also shows less than an opening bid and could not include the possibility of having more than an opening bid. So, in response to 1♣ , bids of Pass, 1NT, 2♣ , 3♣ can be considered comparable as they are of less than opening strength. 1♠ is not comparable as it is a bid that allows the possibility of hands that are opening bid strength or more. So South would have to pass 1♠ at their next turn only (even if East makes a bid).
If North has a hand with 10 points and six spades, and doesn't play Weak 2s, then they may need to risk a bid of 4♠ as South will have to pass any bid involving Spades.
Finally there is an onus on the Offender's partner (in this case South) not to bid in a way that recognises the unauthorised information of the original (withdrawn) Pass (Law 16C2). In this situation this would be hard to do (because North has to bid in a way that shows less than opening values or will silence South's next bid) but if in any doubt the TD should be called.