Change title of Probability OR create alternative Field

Change title of Probability OR create alternative Field

Hi.
We are a Real Estate company. We would like to alter the Probability field to use for a different purpose OR to create another field called "Commission %" for that purpose.

The function of Probability does give you the calculation for an "Expected Revenue". However, this doesn't make sense to us unless it was either titled "Commission %" or we can create a field with this name for the same purposes.

Is this possible? How can I make this?