There are no hard and fast rules, but the assumption is that the story you are pitching is submission ready. So yes, you can take a day or two or three to review and polish as you always want to submit your best possible work, but waiting too long may or may not look odd.
BUT, don't feel any obligation to submit to everyone who "likes" your story. DO YOUR RESEARCH. If the agent or editor doesn't seem like a good fit, don't submit. On many of the pitch parties (I cohost #PBPitch) sometimes you get agent or editors who don't feel "right." A few times a vanity publisher or two hearted a bunch.
Good luck!