# Repay Borrow Behalf

The repay function transfers an asset into the protocol, reducing the target user's borrow balance.

**AErc20**

```
function repayBorrowBehalf(address borrower, uint repayAmount) returns (uint)
```

* `msg.sender`: The account which shall repay the borrow.
* `borrower`: The account which borrowed the asset to be repaid.
* `repayAmount`: The amount of the underlying borrowed asset to be repaid. A value of -1 (i.e. 2 ^ 256 - 1) can be used to repay the full amount.
* `RETURN`: 0 on success, otherwise an [Error code](https://docs.aquarius.loan/atokens/error-codes)

Before repaying an asset, users must first [approve](https://eips.ethereum.org/EIPS/eip-20#approve) the aToken to access their token balance.

**CEther**

```
function repayBorrowBehalf(address borrower) payable
```

* `msg.value` *\[payable]*: The amount of ether to be repaid, in wei.
* `msg.sender`: The account which shall repay the borrow.
* `borrower`: The account which borrowed the asset to be repaid.
* `RETURN`: No return, reverts on error.

**Solidity**

```
CEther aToken = CEther(0x3FDB...);
require(aToken.repayBorrowBehalf.value(100)(0xBorrower) == 0, "transfer approved?");
```

**Web3 1.0**

```javascript
const aToken = AErc20.at(0x3FDA...);
await aToken.methods.repayBorrowBehalf(0xBorrower, 10000).send({from: 0xPayer});
```