Complex sentence: Her mother Gayatri originally believed the email invitation to be a hoax as it arrived at short notice but was eventually reassured by a member of the White House staff and allowed her to travel unaccompanied to Washington.
Split into simpler sentences: Her mother Gayatri originally believed the email invitation to be a hoax as it arrived on short notice. She was eventually reassured by a member of the White House staff, and then Bhimaraju was allowed to travel unaccompanied to Washington.