In order to make your conditional sentences clearer, more colourful or meaningful, there are some adverbial expressions which you can use instead of if.
These expressions are unless, provided that and as long as.
1. To introduce an exception you can use unless.
ex:
We won't renew the contract, unless they improve their service terms.
2. To say that something will remain the same while a condition remains unchanged, you can use provided that or as long as.
ex:
They will accept all of our terms, provided that we assume the insurance costs.
ex:
As long as we have a live account, we can access all the steps of the delivery process.
