Must I wait for form K1 in order to continue?

[MollsBBU]

You have to option to file without it, then file an amendment once it's received although this is not recommended.

Amendment instructions can be found here:  https://ttlc.intuit.com/questions/3061514-how-do-i-amend-change-or-correct-a-2015-return-with-turbot...

You may also choose to file an extension. You can paper file an extension now or wait until our free TurboTax Easy Extension service is ready and e-file your extension. (This free service will be available March 18.)

See below for more information, including the link to the IRS site where you may download the extension if you want to mail it to the IRS:

https://ttlc.intuit.com/replies/3301811