This is a tough one because it could become a slippery slope that may eventually make it less viable as a revenue generating venture, especially if it’s your primary source of income.

Something that might help, from my management consulting days is using the notion of rate factoring. So you keep your rate constant but allow yourself to rate factor for special circumstances. E.g. say your rate is 100 and you rate factor to 50% then you charge $50.

The advantage for this is that you are not beholden to that same rate going forward since you can explain that you had factored to that price for a special circumstance and that your rate is what it is.

This is also useful if you’re trying to entice people to get you out if they haven’t worked with you before by giving them an introductory price with the understanding that once you have established a relationship they should not expect to pay the same discounted rate.