[GAP Forum] Isomorphismtransformationsemigroup

[Mohammad Reza Sorouhesh]

Dear Froum,
My question concerns a certain map say isomorphism on finite semigroups.
GAP has a nice code 'IsomorphismTransformationSemigroup( S)' in which one
can find a possible generic attribute semigroup that is a transformation
semigroup isomorphic to $S$ say $R$. Let $a∈ S$ and let $\phi$ be above
noted isomorphic map. How can I call $\phi(a)$ in GAP? I mean how can I
find the image of $a$ under mapping $\phi$?  I know that this map takes
generator to generator. So that $a$ may be any other element of $S$. I hope
this question is not a very famous duplicate question. Thanks