Submission Dilemma

Hi everyone. I've been lurking for a while now and AW has been really helpful to my submission process. Recently, however, I've run into a problem I've never seen discussed:

My query and my first three chapters have gotten a lot of interest in my first round of agents, and I've gotten a couple of helpful rejections on my full. A recent chat with an agent opened my eyes to some major holes in my manuscript. I've been making a lot of notes, and am excited to make revisions. After some time away from it, I can totally see where the manuscript is lacking, and where this agent was coming from. I anticipate the changes will take me a couple of months at the very least.

Today I got another request off the partial. I don't know how to respond. I don't want to sound unprofessional. I'm thinking I should simply explain the situation and be super-apologetic. . . I know it might be pretty annoying to this agent, but it seems a better option than either A) ignoring the request until my manuscript is ready or B) sending a manuscript that I (now) know isn't ready.

Is this the best way to go? Any advice?

Thanks!

Thanks for your replies!

As I read your advice, I realize I didn't describe the situation clearly enough.

After some personal responses from a few (three) agents who read the full (including an agent who spoke to me on the phone and offered to "look at it again"), I've decided to return to my manuscript and make some revisions. Most of the feedback I got was pretty consistent, and I agree that there are specific elements that still need work. I'm not making revisions based solely on one agent's opinion or with any false sense of security that the agent who phoned will necessarily want to represent the revised version. I want to make the revisions because they make sense to me, and because, frankly, I'm no longer satisfied with the manuscript. Parts of it are just plain dopey. I wish I had this kind of clarity about it before I started querying, but hindsight is 20/20. The agent-response wait gave me the time and perspective to see it.

I stopped querying weeks ago. This other agent I'm concerned about asked for the partial quite a while ago, read it, and is now asking for the full. I don't want to send it because I've already gotten into "major revision" mode and don't want to waste anyone else's time with the old version.

If she were asking me to post the manuscript, I'd probably send it when it was ready with an apologetic note. But since this agent's asking me to email the full, there's really no excuse for delay.

Would it be totally out of the question to respond with a brief explanation and an offer to send the full in a few weeks? I realize that this will make me look pretty unprofessional, but isn't it also unprofessional to keep sending out a manuscript that you know isn't ready? Which is the lesser of the two evils?

I should mention that the revisions I plan to do would not affect the opening chapters that this agent already read.