Sirrono
Try this.
Do a display on DS1, Trunk group and sig group and print the screens first so you have a record of them. Maybe do a backup before you start.
Busy the DS1 location
remove the members from the trunk group
remove the sig group
remove the DS1
change circuit packs for the relevant cabinet and remove the TN464
remove the circuit pack
install the new circuit pack
add the new DS1 - copy relevant entries from your print out
add a new sig group (leave out trunk group entries)
change your trunk group - add the members in
change your sig group again and enter trunk group details
Hope this helps, maybe someone else could double check my suggestion as well