Compensate for repairs

[Demetrius Crisco]

I just moved a tenant into my first rental, and the hardwood floors started coming up, there were two bad spots where they actually buckled. I immediately contacted a floor company and had them come out and give me an estimate for repairs. It is going to take them two days to repair the floors and cost around 2k to get the job done. I felt realy bad about the floors being bad for my new tenants. They currently pay $700 a month for rent. I told them that for the inconvenience of having their home turned into a construction site , I would give them a half months rent. We signed a month to month lease when they moved in, my question is, what kind of documentation do i need to provide that shows I am accepting only $350 for a month of rent. I was thinking about just making a document that states both of our names and explains why I am accepting $350 for a full moths rent and having both of us sign it when i collect the rent.  Is this acceptable?