General Power of Attorney w/ Durable Provision Please explain what initialing…

General Power of Attorney w/ Durable Provision
Please explain what initialing this Provision would do and what it would not allow if it were not initialed? Please put it in plain, and simple terms. The form we have is worded, ”If the blank space in the block to the left is initialed by the Principal, this power of attorney shall not be affected by the subsequent disability or incompetence of the Principal.” Thank you.