If your piano has not been tuned in a while (more than 2 years for most) then you may be in need of a pitch correction before a proper tuning can be performed.
Pianos lose there tune continually over time. The longer they go without tuning and maintenance the further away from their natural pitch they become. If a piano falls far enough then a tuning simply won't do the trick. Pianos are designed to stay where they are. This is normally a good thing as it ensures a piano does not lose its tune right after tuning as you see with other stringed instruments. However, if a piano is already far out of tune this feature has the opposite effect. A badly out of tune piano will resist a simple tuning. The strings will stretch and the piano will fall out of tune almost immediately (normally within 7 days). In order to remedy this a pitch correction brings a piano sharp. We actually tune the piano above what it needs to be set at. When the strings stretch out, they fall within the range that can be successfully tuned.
The only way to determine if a piano needs pitch correction is to measure the tune of the piano. Upon arrival I will take a measurement of the pianos pitch and determine if it can be tuned. If a pitch correction is in order, I will perform the pitch correction that day, and schedule to return a week later for the tuning. This ensures that the piano can stretch and adjust to the pitch correction and helps the piano holds its pitch when it is tuned.
If your piano needs some additional care to return it to its natural pitch, hire an experienced piano tuner that is here to help.