I began 2017 return with turbotax but ended up using accountant as it was complex. How to proceed for 2018 so info is not automatically transferred? Uninstall 2017?.

You can start a New 2018 WITHOUT carrying forward the information from 2017. 

ok thanks. I assume there is an option to do this and no need to uninstall 2017.

correct. Use the easy step method and say no to using software the prior year.

Thanks!