gatekeeper migration and discover

this is being done on an aix host

I am migrating 7 luns from an existing emc san array to another emc san array...and need to remove the old luns

6 luns are gatekeepers and 1 lun is data -- 40 G

I ran config manager on the host and the new luns are showing up from the new array....

I will perform a migratepv to move the data from old 40 Gig disk to the new 40G disk

at this point I will remove disk from vg and rmdev the disk from the aix odm

question is

how to remove the other 6 old 3 meg gatekeep devices?

do I need to move the data from the old pv to the new pv via migratepv

or do I just remove the old gk devices by rmdeving them and them unzoning them?

also, there was a mention of a discovery that is recommended to be done...

how do I do a discovery?

do I run discover after I rmdev all the luns?