Gina, is the bulb firm or mushy? If it's firm then it's still alive and good. If it's mushy it is rotten but if there is still some part of it that is firm cut away the rotten part and replant it. It should still come back if there is at least one eye left.

Thank you for replying to me. It is still firm so I will just leave it alone and wait for it to sprout leaves.

Gina

can you post a picture? sometimes the yellow means its on it's way out...sorry to be a "downer"
the rhizomes should be crisp, fleshy, and fairly white.

I'm wondering why you have a canna in zone 9 that is not potted or in the ground. Either one of those would have kept your canna from freezing and there should have been no worries.