Those wishing to convert ND's to Euros without having approved transaction to spend the Euros on would indeed have to pay a premium ~ that is, indeed, part of the point of a New Drachma reform, in addition to the government being able to spend ND's on direct employment programs ~ but the settlement rate for qualifying tax obligations and contracted payments would remain 1:1.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.

In practice some tradesmen will refuse to accept ND, but most will accept them at a discount.

The thing is that if you take someone to court - over, say, a debt - he would be able to pay in ND rather than Euro, at no discount. So the creditor has a fairly substantial incentive to come to an arrangement.

What this means is that:

1. Debt will be effectively rebased to ND retroactively.
   
2. Large purchases of imported goods - automobiles, machine tools, large-scale engineering, etc. - will instantly transition to the ND footing going forward. But those are typically purchases that can be deferred for a month or two while the monetary system shakes out, without riots in the streets.
   
3. Small purchases, such as going to the grocery store, will transition more gradually, as Euros remain viable means of payment at (or at least not greatly above) pre-crisis prices while the €-Mark/NDrachma exchange rate shakes out.