It's not ideal, but half a dozen days is plenty time enough to get the words to scan decently, figure out whether you need to start high or low, get the tune and the rhythm down, and so-on. Done it before will no doubt do it again.

Probably not long enough to get a whole battery of songs set to heart mind you! But I'd be OK about taking on a couple of songs a few days ahead of a sing, just so long as I do actually do *some practise* *each day*.