I realise this is an old thread but I just found it by googling my problem.

Some time ago our writers' group had a debate about Quotation marks as used with speech. Should text be enclosed with single-quotes;
‘I’d do anything for love but I won’t do that,’ sang Meat Loaf.

Or should we use double-quotes;
“I’d do anything for love but I won’t do that,” sang Meat Loaf.

Some people preferred the former whilst I had been in the habit of using the latter. But, in the interest of uniformity, all the short stories in our forthcoming book were either submitted using, or were converted to, single-quotes. Now I find I have some documents–even whole books–with single-quotes where I’d prefer double. I needed to find some way to reformat long documents automatically.
I considered using the Replace function in MS Word 2003 to replace all instances of ‘ with “ but realised that apostrophes (which, as far as Word is concerned, are identical to single-quotes) would be changed to double-quotes too. This would have produced;
“I”d do anything for love but I won”t do that,” sang Meat Loaf.

Obviously, that’s no good. I searched the good ol’ interweb, convinced that some Bright Spark would have sorted this out with a cheeky wee utility. I found nothing.

So I did a bit of brainstorming and realised that speech quotes and apostrophes are positioned in unique ways with regard to the text that surrounds them. For instance, a ” (double-right quote) is never followed by a letter whereas an apostrophe often is. I won’t belabour the rules I derived since, if you examine the five lines below you should be able to follow my reasoning.

To replace ‘ with “ and ’ with ”, do the following Replace procedures;

Replace…

^p’ with ^p”
.’ with .”
,’ with ,”
?’ with ?”
!’ with !”

Don’t worry that ‘ and ’ look different as do “ and ”. MS Word will automatically decide which is required and choose the correct one for you.

This seemed to work fine, but then I found an exception that lets some text get screwed up;
“Hello, Jim,” he said. ‘How’s life?”

The single-quote before the word How is unchanged. I could use Replace… space/single-quote with space/double-quote.
But then this;
‘Hello, Jim,’ he said. ‘Haven’t seen you ‘round here before.’
Becomes this’
‘Hello, Jim,’ he said. “Haven’t seen you “round here before.’

If I could do the replace only after aspace and before an upper-case letter I’m sure it would work. But I can’t see how Word 2003 would do that.

Now my head is spinning and I’m off for a lie-down in a dark room.

I doubt if Replace is up to all this complexity. Maybe I need to investigate Just Basic.