Technician reported conflicting Revised Engineering Orders caused confusion between Technicians and Engineering. The Aircraft was removed from service for additional maintenance.

Narrative

While Aircraft X was in ZZZ SVL on Date it was noted that during the repair of LH Aileron Rub block disbonding for PWI WXXXXXX & WXXXXXY that the wrong REOXXXX-XX-XX-XXX (aileron P/N 60XXXXXXX-X was used to create the Planning Watch Item for re-inspection and permanent repair. Aircraft X) has LH Aileron installed P/N CCXXX-XXXXXX-XXX/XX which should have had REOXXX-XX-XX-XXY complied with for the re-inspection and permanent repair. Per PMI; PWI were initiated in ZZZ1 on Date1 deferred by Name.Complying with a permanent repair for PWI WXXXXXX and WXXXXXY to LH Aileron Rub Block disbonding. Noted REOXXXX-XX-XX-XXX was not for the P/N Aileron currently installed on this aircraft. Has LH Aileron P/N CCXXX-XXXXX-XXX/XY installed which should have REOXXX-XX-XX-XXY for inspection and permanent repair for creation of PWI.Could have been caused by lack of knowledge that there is two different REO's for dis-bonding rub blocks for different P/N Aileron's which have different re-inspection and permanent repair intervals used on the CRJ200/700/900 fleet.