Consider the following premises. There is at least one z_1 for which z_1 is a poet if and only if z_1 will make tea. For all z_1, if z_1 were a poet, then z_1 is making tea. Can we infer the following from them? There is at least one z_1 for which z_1 is a poet if and only if z_1 will make tea.
That is one of the premises. Therefore, the answer is yes.