"Come over" refers to the action of someone visiting, arriving or attending a place. There are multiple synonyms of this phrase that can be used depending on the situation. If we talk about visiting, then one can use "drop in", "pop in", or "pay a visit". Similarly, "show up", "arrive", or "attend" can also be used in the context of coming over. Other synonyms that can be used are "stop by", "visit", "come by", and "swing by". These synonyms can be used in various situations to express the act of visiting, and each choice can change the tone of a conversation.