Switching FFL's with a Pending ATF Form 4
Switching FFL's with a Pending ATF Form 4 can seem like a simple process. We recently found this question being asked on the Reddit r/NFA subedit. The person posting the question wanted to switch where the silencer was being held from one FFL to their friends FFL. You can switch FFL's for your ATF Form 4 paperwork, but the consequence is that you will need to cancel your ATF Form 4 that is pending/submitted to the ATF. This will lead to you restarting your wait time with the new FFL. If you haven't applied for your tax stamp yet, then the process is relatively straightforward. You will have the FFL that is currently storing your NFA firearm ATF Form 3 the NFA firearm to the FFL dealer where you want to apply from. You may incur transfer fees to make that switch from the FFL that currently has you NFA firearm.
In summation, you can switch your NFA firearms between FFL's, but that process may increase your wait time with the ATF and/or may incur transfer fees from the current FFL where your NFA firearm is being stored at.