The filing deadline for a 1065, Partnership return is March 15th.  Since March 15th is on a Sunday this year, it will be on March 16th.

Your software has errors and I need to file an extension for a 1065 return.  How can I do this with turbotax Business for multi member LLC

Open up your Turbo Tax Business return and open up your original tax return you prepared. Once you are in the return, go to:

1. Federal Taxes
2. other
3. You will scroll through the various questions until you arrive at a page called Amended Return