New in version 5.8.0.x, aliases can be modified directly from the SIL Manager!
To manage SIL aliases in the SIL Manager:
Click the SIL Aliases tab on the right side of the SIL Manager
Click the edit icon on the upper right corner of the aliases panel
Click the plus icon in the upper right corner of the tab to add a new alias
In the newly created row, select a field from the Custom Field drop down list
In the text box (Alias column) add the alias name for the custom field
Click Save
Note
The SIL Manager interface also uses the sil.aliases file. Saving changes from the SIL Manager will cause the sil.aliases file to be overwritten.
A single custom field can have more than one alias