The present invention involves methods for isomerization of 1234zc. Also provided are methods for managing 1,1,3,3-tetrafluoropropene produced as a byproduct in a process for synthesizing trans-1,3,3,3-tetrafluoropropene from 245fa, wherein 1234zc is converted into trans/cis-1234ze with the help of a catalyst in the absence of HF and in an isomerization reactor, or is converted into 1234zc and/or 245fa with the help of a catalyst in the presence of HF in a separate reactor or preferably in the same reactor of 245fa dehydrofluorination.