No creo que a Miguel se le (olvidar) la cita. Si usted le hubiera pedido (pedir) una cita, él me lo habría mencionado. What form of the subjunctive be used? And can you explain why to me?

olvidara

Explanation:

so there's this funny thing in spanish that even though we are in the prensent tense, it "sounds" better with a past tence. so it's more of a sounding phrase.

Hope this helps