I know someone who changed their baby's name at under a year but over 6 months. In this case she realised she was calling him a nickname all the time and there was no reason why the nickname couldn't be the real name. The child is now 3.5 and the new name as totally stuck. Not quite what you were asking though, sorry!! We had a pet name for my bump when pregnant and my son can't get the name of the baby right now she is born.. He k own her name if you ask him but otherwise he refers to her as the bump name. He is 4, the baby is just three weeks.