"BES plans debt-to-equity swap"

Since the 'financial crisis' of 2008, loads and loads of non-financial companies have carried out debt-for-equity swaps, most noteably the Big Three car manufacturers in the USA (Ford $10 billion; Chrysler $2.5 billion; General Motors $27 billion, possibly a bit less than that), but because banks knew that they could con governments into using taxpayers' money to bail them out*, very few banks have done so.

Reuters give us a good recent example of a bank doing a debt-for-equity swap, albeit in a very small way:

Banco Espirito Santo, Portugal's second-largest bank by assets, wants to raise up to 791 million euros ($1.08 billion) capital through an offer to swap debt for stock that could lift its core tier 1 capital ratio close to a 10 percent target...

So you see, it can be done, it's nothing dramatic or anything.

* For sure, the US government also lent/invested $80 billion, but they look set to recover over 80% of that, which by government standards was a stupendously good investment.