1) on your husband dying intestate his 50%share in property would devolve on you and your 2 daughters .
2)your daughters can execute gift deed / relinquishment deed in your favour to transfer your husband 50%share in your name .
3) gift deed / relinquishment deed among family members attract nominal stamp duty .
4) make an application for mutation of flat in your name on basis of death certificate of your husband and gift deed executed by your daughters .
5) if cooperative housing society is formed make application for transfer of share certificate in your name