The phrase "about to be" implies something that is imminent or in the process of happening very soon. Synonyms for this phrase could include "on the brink of," "nearing," "approaching," "almost," "in the midst of," or "in the offing." Other words that convey a sense of imminence or anticipation include "imminent, "impending," "looming," and "forthcoming." Depending on the context of the sentence, more specific terms could be used such as "upcoming," "pending," "preparing for," "planning for," or "getting ready to." Ultimately, the most appropriate synonym for "about to be" will depend on the specific situation and the exact meaning the sentence is intended to convey.