4Yr will not do wee or poo in anything other then nappies

[CoffeeTwin2]

I am at my wits end, I have 4 year old twins, one is totally potty train and even dry at night. But the other one refuses to poo in the toilet or potty only in her nappy. She will ask to occasionally go to wee on the toilet or potty, if I put her in knickers she will try to stay dry but then asks for her nappy when needing to poo. I am really worried as she will be starting primary school in September and I do not know how to get her to poo on a potty or toilet so I can get her out of nappies.
Please Please Please help!! I feel I am failing her

[Piratejones]

pooing in a nappy is really common right into school age, please don't panic about this. Many people have their children in undies but ask for a nappy when they need it.

The first step is to get her to go into the bathroom when shes using her nappy.