I would gently lift her up, or push her up into a standing position, she may try to peck you, watch for chicks under the wings, you will need to see what's under her to decide how to proceed.
Is she is a safe area or in a raised nest, if the chicks can come out and then return under her I would wait, the danger comes if the chicks can fall out of a nestboxes, or climb and can't get back under her.
Hopefully you don't have a staggered hatch where the other hen kept adding eggs. That would end up with some eggs that aren't ready to hatch yet but will get abandoned. It's always best to count eggs and Mark them when a hen begins a hatch.
If all are hatched you can move them otherwise I would figure on moving either before night or within 24 hours depending on where she's sitting.