How do I sign over only my portion of the house I inherited?

You can "disclaim" any specific items that you don't want, or you can disclaim a percentage of the estate.  That should be done within nine (9) months from the date of death of the deceased person.  If it is later than that, you can always make a gift of the property once you receive it, or instruct the trustee (or executor) to deliver the property to someone else.  By the way, if you do a "disxclaimer" you will have no power to say who will receivge the property being disclaimed...  It will pass to others as if you had predeceased the person who had actually died.  Be clear on what you are disclaiming or giving away; don't forget to say that you are retaining the personal property.