In reply to abdelaali_21:
You can change the access rights of individual fields at runtime with set_access.
The only other access rights are with uvm_reg_map. You can have multiple maps for the same registers.
Maybe you need to explain better the reason why you want to change the register rights at runtime, and not use RW to begin with.
You’ll need to discuss this with your RALF tool provider how you might do this.