Complex Transformation:

While you wait here, please remain until I arrive.

Detailed Description:

The simple sentence "Wait here till my arrival" can be transformed into a complex sentence by adding a subordinate clause that begins with a subordinating conjunction, such as "while."

In the complex transformation, the main clause "Wait here" remains the same, but the subordinate clause "till my arrival" is transformed into "while I arrive." This change adds more information and provides a clear condition or time frame for the action in the main clause.

The conjunction "while" indicates that the action of waiting is to be done during the time when the person speaking is in the process of arriving. The verb "arrive" is changed to the present participle form "arriving" to indicate an ongoing action.

The resulting complex sentence is: "While you wait here, please remain until I arrive."

This transformation adds complexity to the original sentence by introducing a subordinate clause that provides additional details and specifies the time frame for the action of waiting.