Well as you will see from my many posts on this topic - its not easy. You will need to write some SQL that updates t_xref, t_objectproperties and t_diagram. See below for a sample (for SQL Server)
pdate t_objectproperties set ea_guid = '' where t_objectproperties.Object_ID In
(select t_object.Object_ID from t_object, t_xref where t_object.ea_guid = t_xref.Client and t_xref.Description like '%DBBPMN1.1%')
update t_xref set description = REPLACE (cast(description as nvarchar (max)), 'DBBPMN', 'BPMN')where description like '%DBBPMN%';
update t_diagram set StyleEx = REPLACE (cast(StyleEx as nvarchar (max)), 'DBBPMN', 'BPMN')where StyleEx like '%DBBPMN%';
This in effect rolls me back to a Sparx standard BPMN1.1 profile. I've done this because i then want to run the migrate function to upgrade from 1.1 to 2.0 (ill then have to run further SQL to migrate to the v2 version of my profile).
This will only work if your profile has elements as defined in the Sparx profile - ie Activities, Events, Lanes, Pools etc - ie its an extension of the Sparx profile.
Regards
Jon
Ps backup before - i accept no liability this advice breaks your system!