Hi , I wait for the old bloom stem to turn brown then cut it off about 1 inch from where it attaches to the plant . I would re-pot then you know how long it has been since it was done .. Your bloom is very pretty I forgot to say be sure to not use a pot that is too big .Just big enough for the roots to fit in it or a small bit of extra room being they like to be moist to much mix around it equals root rot ..
Gin, thanks. It is in a very small pot, 3", and I am anxious to see what the root structure looks like. I will wait for the stem to brown up, cut, then repot.
I personally don't believe it's necessary to wait for the stem to dry out before cutting it. Since you don't have a seed pod on it and the flower has already fallen, the plant no longer has a need for it.
Also, when you repot, remove any dead or decayed roots
(you'll know, they'll be soft and mushy) before repotting.
Go easy on the water for the first few weeks to give any roots bruised in the repotting a chance to adapt and grow.