There are certain times when you may need to take a distribution from a Solo 401k.
Please note, these instructions are specific to an early or normal distribution only. If you are rolling funds out to another retirement plan, doing an in-plan Roth conversion, taking an in-service distribution, or taking a participant loan, the procedure is different.
These articles will help with those specific topics:
When you're rolling funds out of the Solo 401k the basic process is:
Determine how much you're rolling out of the plan
Fill out the form "NAB Distribution Form" in your Solo 401k plan documents
Move the funds from your Solo 401k account to the new retirement account via check/ACH/wire, etc.
In January of the following calendar year you and your CPA/tax advisor will generate a 1099-R documenting the rollover
Please note all distributions from a (traditional) 401k plan are taxable. If you are distributing funds before you reach age 59.5, you will incur an additional 10% early withdrawal penalty.