QueenOfCoach / fotographer / DMPHL / AndyAA / SeattleDavid / enpremiere -- thanks so much for all your posts and input above. I'm genuinely grateful.

It seems that, for the most part, it is a real gamble to cancel a hold in the hope of being able to re-hold the same award: I could get lucky, but the odds may not be especially good. I've had a look on BA.com and can see no availability for the award that I currently have held (and would like to re-hold), and awardnexus is showing nothing as well. So, it would seem a bit of a lottery to try to re-hold, especially as, were I unable to locate the award that I had just cancelled (for re-holding purposes) on AA.com, then I'd find myself with no means of returning home (at least in terms of an award flight).

Thank you all for enlightening me about the risk -- I had wrongly assumed that it might be almost risk-free.

All the best