I assume you're talking about elective surgery in a public hospital? As for what happens to you personally when you've gone past the recommended waiting time - nothing in particular, you still just have to wait on the list. (I think the hospital gets penalized when a certain percentage of people wait too long, not just one or two.

You should definitely contact the hospital to check though. There's usually an elective bookings office or clinical liason nurse who handles these type of enquiries. Occasionally paperwork gets lost or mistakes happen so it's really worth checking. Also you may have some chance of getting in earlier if you tell them you're available at short notice.

If you feel like there's a good medical reason your operation should be done sooner eg. worsening pain or other symptoms then ask your GP to contact the hospital doctors on your behalf and see if they can prioritise you.