C#

Question

I made an application using windows form application in C# . it will ask some question from use in form and based on their answers it will connect to the proper SQL tables and will use some data for some calculation and finally will sort data tables and show them to user...now I wanna ask you if I wanna sell it to a company or sell it to the online shopping websites should I rewrite it again in another way with other software or not? what is better solution for this?