First take a look at the linkagg:
BR-02-> show linkagg
Number Aggregate SNMP Id Size Admin State Oper State Att/Sel Ports
-------+-------------+---------+----+------------+--------------+-------------
127 Dynamic 40000127 16 ENABLED DOWN 1 1
BR-02-> linkagg lacp agg 127 admin-state disable
Then remove the ports currently in the dynamic linkagg (for me it was just one port - 2/12):
BR-02-> no linkagg lacp port 2/12
You then should be able to remove the linkagg entirely:
BR-02-> no linkagg lacp agg 127
However, like me, you may see the following error:
BR-02-> no linkagg lacp agg 127
ERROR: Aggregate has Service config
Take a look through your config for any auto-generated lines related to the linkagg group.
BR-02-> wr t | grep linkagg
linkagg static agg 1 size 2 admin-state enable
linkagg lacp agg 127 size 16 admin-state disable
linkagg lacp agg 127 actor admin-key 65535
spb isis interface linkagg 127
In my case I had to remove that last line:
BR-02-> no spb isis interface linkagg 127
And then repeat the linkagg removal command:
BR-02-> no linkagg lacp agg 127