We are a mid-sized nonprofit, and are in the middle of our first financial audit. We have been looking into new firms for a few months now, and have found one that we like. For a number of reasons, we'd like to transition to the new accounting firm now, rather than wait until the audit is over. 1) Would transitioning now send a negative signal to our auditors? and 2) Is this too tricky of a transition to manage during an audit, or is is manageable as long as we are conscientious about how to structure it? Any advice, tips, guidance is much appreciated!

Changing accounting firms in the middle of an audit
Answers
1) Yes. 2) Not recommended, but why are you looking to change firms? I have not hear of someone changing firms in the middle of an audit unless for a very good reason.
I agree with Carla. It is my experience that audit firms are 'territorial'. Each entity has a bias towards finding fault with the prior auditor's work. In addition, it may well have different testing methodologies, sampling formulae etc,. So, you are setting your self up for extra cost and time.
If you are determined to change, then I suggest, to the extent you can,that you get agreement from the current firm to provide all working papers in a timely fashion, and get the new firm to agree to accept the work already done. I have not had much success with this attempt but one never knows
Even if your organization ignore the initial concern of raising red flags , there is the need for the proposed accounting firm to request in writing from the existing auditor any ethical among other reason for not wanting to continue . Besides, relationship matters and transparency and effective communication are very important. matters .
The existing audit firm is probably not going to provide copies of incomplete working papers, and the second firm is almost certainly not going to rely on partially-complete work done by another firm. In other words, you would have to pay the first firm for work done to date, and then start over from scratch with the new firm. There would be additional cost, from the duplicated work and fees, but also additional work for your employees to support the duplicated test work. You would also likely delay completion of the audit.
If there are strong reasons to change auditors, it may still be the right decision to change sooner rather than later - just make sure you are realistic about the cost and time implications.
Are we talking moving the accounting and advisory CPA functions or the Auditor functions.
Many companies (public/private/non-profit) have two different public accounting firm: Advisory and Audit.
Which aspect do you want to move?
Thanks for the responses everyone. To Wayne's point, I did not make clear in my question that this is the advisory and advisory CPA firm I am thinking about changing, not the audit accounting firm. My apologies for the confusion on that.