Yes, plastids ate interchangeable in their form. Generally, three types of plastids arepresentin plantc ells, i,.e., leucoplasts (storage), chromoplast (coloured) and chloroplasts (synthesis of food green pigment).
Depending upon the circumstances, one type of plasmid may be converted into another type. e.g.,
(i) In Capsicum, the cells of ovary consist of leucoplasts. When ovary changesinto fruit,leucoplasts are transformed into chloroplasts. When the fruit ripens chloroplast areconverted into chromoplast.
(ii) The leucoplast in stem tubers of potato, on exposure to sunlight transform tochloroplasts.
 in some cases the chloroplasts gets converted during ripeningof fruits, e.g., tomato chilli when they change colour from green to red. In occurs because of chlorophyll and degeneration of lamella.