You can replace nucleus members by using a combination of INCLUDE and EXCLUDE statements. To replace one member with another, take the following steps:
EXCLUDE oldmod
INCLUDE newmod
The oldmod is a member of SYS1.NUCLEUS that was to be included through either an MLT or an NML, and newmod is a modified copy of oldmod and also is a member of SYS1.NUCLEUS. Note that a different member name is used for the modified copy specified on the INCLUDE statement.