If you believe a direct quotation contains a typographical, orthographical, or grammatical error, the polite thing to do is to quote it as it stands with the error labelled by a "[sic]" (written in square brackets, as shown).

For example, if I felt "Imagine it was you. Why might you do it?" should be "Imagine it were you. Why might you do it?", I would write along the lines of:

Imagine it was [sic] you. Why might you do it?

By that logic, you ought to spell phoenix "pheonix", regardless of what the Oxford English Dictionary tells you.