Against, b'kitzur nimratz.
Before he met Esther the watchman on the women's house was הגא with an aleph.
After meeting Esther he became הגי with a yud - evidently indicative of a his'alus.
But we know that the yud taken from Sarai complained until it was affixed to the beginning of Yehoshua.
So where did the aleph from Hegeh go?
It went to Bigsan.
In the beginning of the Megillah he is plain בגתן.
When the story is read to Achashveirosh he is בגתנא.