Formula to Autofill Value Based on Another Cell

I solved part of this but not the second part. I have these three columns on a document I am working on. I need a formula to do two things:

1. If Column I lists a frequency (Annual, Biannual, Triannual) then K will autofill the next review date based on the date in Column J.
2. If Column I lists TBD, then Column K should also autofill with TBD. In this scenario, Column J will remain blank.

The formula I have so far is =IFERROR(EDATE(J2,LOOKUP(I2,{"Annual","Biannual","Triannual"},{12,24,36})),"")

(I'm using IFERROR to hide the #NA returns in the blank cells.)

I can't figure out what formula to add in to return a value of TBD instead of a date if Column I is TBD.