Can I change Due Date? I need to change this to the 1st of every month.

I am landlord and lease was signed for rent to be due on the 15th of every month. I need to change this to the 1st of every month, since my mortagage for the house will be due on the 1st also. Am i able to do this?

You can if the tenant agrees to this. If he doesn't agree, you can't change this date.

If he does agree, accept only a half month's rent on the 15th, and mark his receipt to show the rent is paid from the 15th to the 31st of the month. Then write on the receipt that a full month's rent will be due on the 1st of the month thereafter.

This is a simple change and most tenants have no problem with it, especially since they only have to pay 1/2 the rent they were planning to pay on the 15th.