Thank you for your answer. However, I am not clear so I just reproduce your reply to my query. Because in one of our office circulars it was used to congratulate one on one's promotion. I reproduce that too.
Please join me yet again in extending my congratulations and sharing my pride in announcing ...... as a Senior Associate of the Firm ! If "yet again" tends to be used with negative things, is this sentence right?
'Yet again' tends to be used with negative things, so 'once more' would probably work better.
Waiting for your advice.
"yet" has about six meanings, and in the context we're dealing with it's ambiguous. It's synonymous with both once and still. The latter synonym, still means, not moving, and given our context, "extending congratulations yet/still again" implies there was a first (or even second) attempt at extending congratulations that wasn't successful. That's why "once", meaning one more time, would be a better choice for that particular context.