Let's denote the total number of parks as \( P \). According to the report, \( \frac{1}{3} \) of the parks have flagpoles.
So, the number of parks with flagpoles is:
\[ \text{Parks with flagpoles} = \frac{1}{3}P \]
Now, if the school decides to install flagpoles in another one over three of the parks, we interpret "one over three" as \( \frac{1}{3} \).
This means the school will install flagpoles in \( \frac{1}{3}P \) additional parks.
Now, we need to calculate the total number of parks that will have flagpoles after this installation:
\[ \text{Total parks with flagpoles} = \frac{1}{3}P + \frac{1}{3}P = \frac{2}{3}P \]
To express this as a fraction of the total number of parks, we take:
\[ \text{Fraction of parks with flagpoles} = \frac{\text{Total parks with flagpoles}}{P} = \frac{\frac{2}{3}P}{P} = \frac{2}{3} \]
Thus, the total fractional portion of parks that have flagpoles after the installation is:
\[ \frac{2}{3} \]