According to the current documentation (https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/dev-itpro/data-entities/dual-write/dual-write-troubleshooting-dual-write-module#error-when-you-link-the-environment-for-dual-write-or-add-a-new-table-mapping), only the user who set up Dual-write initially is able to add a new table mapping. A system admin is only able to edit table mappings.

This is poor user experience - admins are allowed to unlink the environments but they're not able to add a new mapping. There may be some technical reasons behind this but few user would consider it good design.

Requesting to allow new table mappings to be added by users other than original admin.