We have just started to try and transition to one nap at almost 14 months old as our little girl was beginning to do two shorter naps. Today she was asleep at 11.45 (woke at 7am) and did 1.5 hours (she woke crying in the middle but she often does this anyway) and then woke really screaming after 1.5 hours as clearly still tired. Resettling doesn't work as if you go in she just wants to come out of her room. How long does it take for them to get used to one nap and when will she learn to do a longer one of two hours? I can't remember from my son but his naps were always hard work until he was used to one nap a day of two hours 1-3pm (took us a long time to get to that though).