First, open the command prompt with administrative privileges.

Type ntdsutil and press Enter.
Type roles and press Enter.
Type connections and press Enter.
Type connect to server DC01 and press Enter, where DC01 is the server computer name that will transfer the FSMO roles to.
Type quit and press Enter.

Next, we will transfer FSMO roles one by one with the corresponding command, as the case may be. After each Enter appears a confirmation window. Just click Yes to continue.

For Schema Master, type transfer schema master and press Enter.
For RID Master, type transfer rid master and press Enter.
For Domain Naming Master, type transfer naming master and press Enter.
For PDC Emulator, type transfer pdc and press Enter.
For Infrastructure Master, type transfer infrastructure master and press Enter.