You can change a personal care agreement at any time. To make a change, both of you have to agree. If you both want to make a change, simply write a note explaining the change -- more or less pay, more or fewer hours, different tasks -- with both of you signing and dating the note, and attach it to the original contract. Or if you find that you both want a number of things to be different, you can draw up an entirely new agreement. If you do draft a new contract, include the phrase "This agreement supersedes all previous agreements between the parties having to do with personal care."