When converting a document from British English to American English I ran into the following problem with the quote marks: all attempts to automate the change (Search&Replace or by a Macro) resulted in every opening quote being converted to a closing one!
Manually typing an opening quote works ok.
By doing the S&R conversion as single-quote to TWO double-quotes I got a closing quote-opening quote pair in the document. Deleting the first one (the closing quote) resulted in the remaining one immediately changing from opening to closing.
As the document I'm working with has 470 opening single-quotes I'm not very keen on doing the job one quote-character a time; so all help will be appreciated!
_Lup

Note: LibreOffice did the conversion with no immediate problems. But later the converted document caused Grammarly (A grammar check program) to crash(multiple tries!); so that solution is not viable.

Same problem on to two PCs. HP Envy and Elitebook, 64bit, Windows 10 Pro, Office 365 (64 bit on the Envy and 32 bit on the Elitebook)