Subsequently in due course of time after the disciple has gradually advanced step by step from sraddha to sadhu-sanga to bhajana-kriya to anarta-nivritti to nistha to ruci and then asakti and achieves the requisite accreditation for entrance to the platform of raganuga-bhakti then if providence is propitious and one has the adhikara to achieve bhava and fortuitously along the way had the opportunity to develop some delightful mood full of fragrance, some requisite aroma in their bhakti that is irresistibly attractive, then the Supreme Lord Krishna by His  own sweet will, may spontaneously activate their siddha-deha simultaneously inspiring the living Vaishnava acharya diksa-guru who has himself received cognition previously to bestow cognition upon his disciple. So it should be clearly understood that it is only by the grace of guru-krsna-prasade that the siddha-deha can ever be attained. One has to somehow or other attract Krsna's attention. One must do something or feel something so special that one's internal devotion makes Krsna take notice. There is no formula for this. There are no rules about how. There are no regulations one must learn. There are no directives to be followed. There is no manual giving instructions. It can manifest in any way. It could be sublimely subtle as the inner mood one possesses while lovingly following the instructions of the Vaishnava acarya or it could be an astonishing epiphany such as realization of the oneness of nama and nami or it could be a monumental achievement of devotion that gives joy to the Vaishnavas. Yet however it manifests it will be extremely intimate and personal and will manifest only from that purified heart melting with devotion. One thing is certain and that is Lord Krsna is very affectionate to His surrendered devotees and is always on the lookout to find a reason to bring His totally surrendered bhaktas quickly back to him. That is why He is acknowledged as bhakta-vatsalya.