[(rooted) Galaxy S4 verizon SCH-I545 5.0.1] switch custom recovery from CWM to TWRP

i recently rooted my Galaxy S4 verizon SCH-I545 5.0.1 My main reason for doing so is because i want to install CM12 (to improve battery and no bloatware) but need to back up my stock ROM before wiping anything, so i can restore if anything gets messed up but when i installed CWM via ROM manager app , i booted in recovery only to discover that i didn't have the option to back up my stock ROM...nothing that says "back up and restore" or anything remotely close...so after alot of reading a searching it looks like TWRP was the one that most suggested for my phone. My question is, can i just use Flashify and flash TWRP over the existing CWM?? will this mess anything up or brick my phone??? please help and excuse my ignorance