Sole P CAN'T be transfered to someone else, because it can only be related to the owner.
But your business partner can start an OWN Sole P* and the old Sole P can SELL the business assets to the new one (except it can't be exact same name). The assets selling just need to be dicumented as a common big sell.
I don't know if the officials demand you to sign anything to let the new Sole P name have any similar name as your Sole P, IF he want that.
Plus perhaps he want you to sign a not competition document (with time limit) not leting you having a business compeeting with his.
NOTE ! You can keep your Sole P if you want to be used for something, BUT if so you will have to go on doing all demanded tax forms and such. To stop that you have to UNREGISTER your business proper. (I don't remember how, but it surely include BIR.)
*He better try to start the new as BMBE if possible, because such has important benefits. The barangay/municipaly office handle such so they know the demands to be approved as BMBE.