Seize operations master roles
You cannot use AD DS snap-ins to seize operations master roles. Instead, you must use either the ntdsutil.exe command-line tool or Windows PowerShell to seize roles.
To seize or transfer the FSMO roles by using the Ntdsutil utility, follow these steps:
Step 1: Sign in to a member computer, in our case DC2, that has the AD RSAT tools installed, or a DC that is located in the forest where FSMO roles are being transferred.
Step 2: Select Start > Run, type ntdsutil in the Open box, and then select OK.
Step 3: Type roles, and then press Enter.
Note:
To see a list of available commands at any one of the prompts in the Ntdsutil utility, type ?, and then press Enter.
Step 4: Type connections, and then press Enter.
Step 5: Type connect to server <servername>, and then press Enter.
Step 6: At the server connections prompt, type q, and then press Enter.
Step 7: To seize the role: Type seize <role>, and then press Enter.
In our case we type: size schema master.
Step 8: At the fsmo maintenance prompt, type q, and then press Enter to gain access to the ntdsutil prompt. Type q, and then press Enter to quit the Ntdsutil utility.
Reference:
https://learn.microsoft.com/en-us/troubleshoot/windows-server/identity/transfer-or-seize-fsmo- roles-in-ad-ds