The phrase "planning on" can be replaced by a variety of synonyms, depending on the context and tone of the sentence. Some possible alternatives include "intending to," "aiming to," "hoping to," "expecting to," "preparing to," "deciding to," "considering," and "contemplating." Each of these phrases conveys a slightly different meaning, so it is important to choose the one that best fits the situation. For example, "I am preparing to take my final exams" suggests a sense of urgency and readiness, while "I am considering changing my career" implies a more exploratory, undecided mindset. Whatever the case may be, these synonyms can help writers add variety and depth to their language.