To make a lead active after it being turned inactive, click the Mark Active option in the actions menu of the inactive leads table.

Choose an inactive lead that you want to activate, and click on the Make Active option from the lead table.

To view the inactive lead all the inactive leads by selecting the checkbox labeled as Display only inactive on the left and clicking apply.

Enter a comment explaining why you are activating the lead, for future reference.

Finally, click on the Save button. The lead will be made active and can be converted to a potential tenant. 

To make a lead inactive, you can click on Mark inactive from the actions of a particular lead.

Choose the desired lead and click the Mark inactive option.

In the following popup type in a comment explaining as why you are making this lead inactive, for future reference.

Click on the Save button when you are done.

Inactive leads will be displayed under the "Display only Inactive tab"