Override a Lookup Field

[bssmaster8]

I am working on a project for a service company. I have a table with clients and then a table of projects that are linked back to the client. Clients are assigned a rate based on different factors. The rate is carried through to any of the projects they are linked to via lookup field. However, I would like to override the lookup field should we have a promotional rate or a specific project needs to be billed at a different hourly rate. 

Any suggestions?

[TheTimeSavingCo]

Create a number field where you can key in the override, and then create a formula field that'll use that value if it exists and use the lookup if it doesn't:

IF(
  {Rate override},
  {Rate override},
  {Rate (from Clients)}
)

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