If I am correct, you might be OK. Here is my thought process.
Reagent 2 is a base used to raise the pH. Reagent 3, which is probably EDTA, is the calcium titrant. Mixing Reagent 3 with Reagent 2 neutralizes a bit of the base but more importantly, all future tests will require slightly less titrant.
The conclusion is that future test results will likely underestimate the true calcium concentration a bit. If you are going to lose sleep over this, buy a new kit. Otherwise, measure the calcium level more often and use up the kit more quickly.