Yes, I would do as dougall suggests. Snip off the most yellow or any mushy leaves at first.
How are the rhizomes attached to wood or rocks? Sometimes rubber bands or too tight thread can cause problems. But it can also just be a matter of the plant getting used to your tank conditions. Have you had it for long? Say 2-3 months or so?
Sometimes if the leaves "melt" but the rhizome is still healthy it will begin to grow happy again. The only time I truly killed an anubias was when it had a dark brown thread or 3 inside within the rhizome...a rot from inside? I couldn't figure out how to stop it. No matter how far I cut back the rhizome to healthy tissue it came back. I finally just threw it out...too much bother for more sickly plant rescue attempts