稅法隻是說exchange的5年內不能用Section 121 exemption，沒有語言說不讓convert to primary。 當然不同人對稅法有不同解讀可以理解。
(10)Property acquired in like-kind exchange
If a taxpayer acquires property in an exchange with respect to which gain is not recognized (in whole or in part) to the taxpayer under subsection (a) or (b) of section 1031, subsection (a) shall not apply to the sale or exchange of such property by such taxpayer (or by any person whose basis in such property is determined, in whole or in part, by reference to the basis in the hands of such taxpayer) during the 5-year period beginning with the date of such acquisition.
