T-Shoot Exam

I know they have removed the abort option that allows jumping between tickets, but I have a question about exam itself.

If I stay in a ticket and I decide that the issue is with R4 and then I choose the tech issue but see then realise that I may have missed something, am I allowed to back out (within the same ticket) and choose for example R3 or am I locked into R4 as this was my first choice?