Oil explorer Gulf Keystone Petroleum said it has given its lenders more time to accept an incentivised offer to accept changes of $250m (£167m) of loan notes.Earlier in March, the London-listed group announced it was set to breach a technical covenant of the debt in a bid to amend the loan terms with its lenders.Among the reviewed loan terms, the Kurdistan-based oil firm included an "early consent fee", which would see lenders receive $5 for every $1,000 of the loan principle if they agreed to the proposed changes before 23 March.The group has now extended the deadline to 1 April, adding that a meeting of lenders will be hold to vote over the firm's proposed changes.Under the previous agreement, lenders accepting the changes between 23 March and the current deadline, would have received $1.50 for every $1,000.The loan notes carry 13% interest and are due in 2017.Gulf Keystone shares were up 1.84% to 37.30p at 09:05 on Tuesday.