if(pledgeId >= pledgesIndex()) revert Errors.InvalidPledgeID();
address creator = pledgeOwner[pledgeId];
if(msg.sender != creator) revert Errors.NotPledgeCreator();


Pledge storage pledgeParams = pledges[pledgeId];
if(pledgeParams.closed) revert Errors.PledgeClosed();
if(pledgeParams.endTimestamp <= block.timestamp) revert Errors.ExpiredPledge();
if(newEndTimestamp == 0) revert Errors.NullEndTimestamp();
uint256 oldEndTimestamp = pledgeParams.endTimestamp;
if(newEndTimestamp != _getRoundedTimestamp(newEndTimestamp) || newEndTimestamp < oldEndTimestamp) revert Errors.InvalidEndTimestamp();


uint256 addedDuration = newEndTimestamp - oldEndTimestamp;
if(addedDuration < minDelegationTime) revert Errors.DurationTooShort();
uint256 totalRewardAmount = (pledgeParams.rewardPerVote * pledgeParams.votesDifference * addedDuration) / UNIT;
uint256 feeAmount = (totalRewardAmount * protocalFeeRatio) / MAX_PCT ;
if(totalRewardAmount > maxTotalRewardAmount) revert Errors.IncorrectMaxTotalRewardAmount();
if(feeAmount > maxFeeAmount) revert Errors.IncorrectMaxFeeAmount();
+   if(minAmountRewardToken[rewardToken] == 0) revert Errors.TokenNotWhitelisted();
