When my best friend passed away last year, after some months I was given her Xmas Cactus plant. I had seen this plant growing in her home for at least four to five years and saw how beautifully it blossomed. I was amazed to see that this huge plant was sitting in a very small pot--about a 3 inch pot. It has again blossomed and is about finished and I am wondering whether it should be transplanted and what is the best care for it. It is a lovely thriving plant but I am afraid I am noticing some of the older leaves beginning to become a lighter green. I want to save it. What should I do??