Switch 1:

[5500-EI]fabric-port g1/0/51 en
[5500-EI]fabric-port g1/0/52 en
[5500-EI]change self-unit to auto-numbering
[5500-EI]change self-unit to 1
 The unit 1 already exists in fabric.
 Continue? [Y/N] Y
 Info:It is recommended that you reboot the device after you change the unit ID and synchronize the configuration.
[5500-EI]
%Apr  2 00:27:23:426 2000 5500-EI FTM/3/FTMCHID:- 1 -Change unitid successful, unit 1 saved UnitID in flash!
[5500-EI]

If apply: [5500-EI] change unit-id <current_unit_number> to <new_unit_number>

Saved Configuration:

<5500-EI> fabric save-unit-id
 The unit ID will be saved to the device.
 Are you sure? [Y/N] Y
 Unit 1 saved unit ID successfully.
<5500-EI>

Switch 2:

[5500-EI]fabric-port g1/0/27 e
[5500-EI]fabric-port g1/0/28 e
[5500-EI]change self-unit to auto-numbering
[5500-EI] hange self-unit to 2
 Info:It is recommended that you reboot the device after you change the unit ID and synchronize the configuration.
[5500-EI]
%Apr  8 23:12:16:928 2000 5500-EI FTM/3/FTMCHID:- 1 -Change unitid successful, unit 2 saved UnitID in flash!
%Apr  8 23:12:18:357 2000 5500-EI IFNET/5/BOARD:- 1 -Board 0 has been removed
[5500-EI]

Saved Configuraton:

<5500-EI> fabric save-unit-id
 The unit ID will be saved to the device.
 Are you sure? [Y/N] y
 Unit 2 saved unit ID successfully.
<5500-EI>

— David Gonzalez 2021/03/29 15:03