Hi, I want to know if i can manual start retrieval video from an edge device into the Recording Server. Thanks.

You can.

Using the Smart Client you can ask for retrieval of footage when in playback mode, below the export button there is a retrieve button.

Using the MIP SDK please explore the Remote Retrieval Task sample. http://doc.developer.milestonesys.com/html/index.html?base=samples/remoteretrievaltask.html&tree=tree_2.html