However, you could use a combination of initials to represent this phrase, such as:
* SOB: (Signing On Behalf)
* S/O: (Signed On Behalf)
* SBO: (Signed By Other)
Important Note: These acronyms are not standard and might not be understood by everyone. It's best to clearly state "Signed on behalf of [Name]" or "Signed by [Name] on behalf of [Organization]" to ensure clarity.