What if i buy as cnc and sell as mis on same day or after some days

While buying i selected CNC so while selling do i have to select CNC or can i also choose MIS

CNC and MIS is 2 other types of order. If u buy in CNC and sell in MIS then it placed 2 open orders. CNC is not squaredoff. You hv to sell in CNC if bought in CNC and same for MIS.