We have a switch stack on 2nd floor, consisting of 3 MS-250-48FP switches.
The other switch is on the 1st floor and it is a MS-250-48FP.
The 2nd floor switch had switch-1 ports 49 and 50 as a LAG to 1st floor switch ports 49 and 50 respectively.
I wanted to move 2nd floor switch-1 port 50 to 2nd floor switch-3 port 50. I performed the split of the ports on the stack.
Then on the 1st floor I did nothing to the switch LAG, as no changes were required.
On the 2nd floor stack, I completed the split, then moved the SFP to the 3rd switch port 50.
Then I selected the 2 ports switch-1 port 49 and switch-3 port 50 and aggregated them.
Of course Port 50 is down because of LACP.
I do not know how to remove port 50 from the connected ports on the status of port 50.

