I entered USA on H-1B and changed the status from H-1B to H-4. Now I would like to change my status back to H-1B once I get the job confirmation. I have to file “change of status” from H-4 to H-1B and it won’t be subject to CAP as I previously held H-1B status, am I correct?  Will be any time limit for this status change? Will there be any risks involved with this status change that I should be aware of?

You are correct; Yes, you will be able to obtain H-1B extensions for a maximum of 6 years; We cannot comment on risks without first carefully evaluating your situation. However, most COS petitions are relatively straight forward.