I would leave the keiki on the mother plant and let them grow from both groth points. You don't have to remove it. I have a Phal brother lancer that I can tell is a keiki growing off of the old crown. The mother plant must have gotten crown rot. I recieved the plant in its current condition, and its now flowering for me. I have seen several phals growing with no problems that have basal keikis on them the size of the plant and both are flowering. If the mother plants crown is ok then you will have twin plants side by side and then double the flowers in about the same space. I hear its hard to remove a basal keiki, but not imposible. It will eventualy devide itself if left there long enough considering phals only keep a few leave anyways while continueing to grow up, or down if they are in the wild. Unlike vandas that keep alot of their leaves and continue to get taller. If it was me I would leave it till it tells you its time to devide, unless you just want two plants. Have fun.