removing an attribute

RouterOS 6.46.7

This keeps vexing me as I keep forgetting the exact incantation, so I wanted to post the solution here for people to find:
the short answer is to use “” (not ‘’)

For example, I want to change

/interface bridge vlan
add bridge=DevMgmt-bridge tagged=ether1 untagged=ether3 vlan-ids=116

to

/interface bridge vlan
add bridge=DevMgmt-bridge tagged=ether1,ether3 vlan-ids=116

I’ve found sites that say “unset” and others that say ! but neither work:

/interface bridge vlan> unset 0 untagged
bad command name unset (line 1 column 1)
/interface bridge vlan> set 0 tagged=ether1,ether3 untagged=!ether3
input does not match any value of interface
/interface bridge vlan> set 0 tagged=ether1,ether3 !untagged
syntax error (line 1 column 28)

I can’t set it to blank either:

/interface bridge vlan> set 0 tagged=ether1,ether3 untagged=
failure: interface cannot be in tagged and untagged at the same time
/interface bridge vlan> set 0 tagged=ether1,ether3 untagged=‘’
syntax error (line 1 column 37)
/interface bridge vlan> set 0 tagged=ether1,ether3 untagged=none
input does not match any value of interface

The working solution is:

/interface bridge vlan> set 0 tagged=ether1,ether3 untagged=“”