(a) That's right. If a business has been started as a sole proprietorship, and the owner later wishes to operate that business under a different business structure, this can be done. In fact, it is often a good idea to start a small business as a sole trader, to keep expenses low until the business takes off to the extent that justifies a different business structure. Then, depending on the circumstances, the sole trader might decide to enter into a partnership with another person, or form a company to take over the business.

In the present case, for example, if Edward decided that he wanted to join forces with another person rather than continue to run the business on his own, a partnership might be suitable.