"This map can't be revised or extended"

Revision and Add a service both build on the map's stored workflow outputs. Very early Workflow Maps predate output storage, so there is nothing for either action to build on. Those maps show this message: the map has no stored workflow outputs, so it can't be revised or extended, and needs to be regenerated first.

How to regenerate

Regenerating is a normal generation from Create Business with the same intake, at one credit per service. Nothing about the process is special; you are producing the map again on the current system, which stores outputs as a matter of course.

After regeneration

One regeneration is all it takes. The new map stores its workflow outputs, and both Revise and Add a service work normally from then on.