This is an SMPE install and the problem occured after the full installation so it cannot be backed out.
Do you mean you've already done the ACCEPT? If not, then of course you can REJECT and APPLY again later! If you did the ACCEPT before completing testing, WHY???
I've been dealing with SMP/E for a number of years and have never seen the term "full installation" in any of its documentation -- not from IBM, not from CA, not from anywhere. I've seen RECEIVE, APPLY, APPLY CHECK, ACCEPT, REJECT, LIST, ... but never "full installation".