If it's the only type of transistor in the circuit, the translation is straightforward; build the circuit as designed, reverse the power connections and any other polarised components (diodes, electrolytic caps).
If you need one PNP in a mostly NPN circuit, there is no general solution.
There may be solutions, depending on the configuration of the PNP stage.
For example, if the PNP transistor was being used as an emitter follower, and you have the headroom, you may be able to use an NPN in common emitter, with Rc=Re so that its gain is (approx) 1.
If the PNP transistor was in a complementary power output stage but you can only find low power PNP transistors, I remember seeing an arrangement using a PNP driver transistor and an NPN power transistor to "replace" the non-existent PNP power transistor. Peter Walker did this around 1970 for the Quad 303 power amp (I believe 3 transistors were involved) when there was no PNP version of the famous 2N3055.
And there may be other such substitutions.
It's a small signal AC model, so the DC currents don't matter. Since \$ \frac{dI_{C}}{dV_{BE}}\$ is the same polarity for both, we can use the same model (i.e. a larger b-e voltage results in a larger load current, just they are both negative for the PNP version (which equates to the same result as the NPN)
Best Answer
There have been times when transistors with specific characteristics were feasible in NPN, or PNP, but not vice-versa.
Two examples :
The 2N3055 power transistor was NPN, at a time when PNP transistors of the same power were simply not available (115W I think, later pushed to 150W).
That led to the "output triple" - a combination of 3 transistors that could replace either NPN or PNP output transistors, with the power handled in either case by the 2N3055. This was used in the famous Quad 303 amplifier of the early 1970s.
Another example : the BC214 PNP transistor could achieve lower noise in a microphone amplifier or audio input stage than contemporary NPN transistors.
With further developments in process technology, these considerations are less important than they were.