Yes you can but you must be aware of the power of pcr to amplify. Every 10 cycles of pcr is 1000 times more product so if re amplifying you should dilute 1:100 and amplify 1ul of the diluted product and run a range of cycle numbers. Set up 6 tubes of pcr and remove one tube after 12 cycles,one after 14 cycles etc to see where the best amplification happens. If you run too many cycles you will get a high molecular weight smear instead of a clean band . This smear is product annealing with other product molecules and making longer products
Yes you can after sample dilution but is preferable that you are using for both PCR an high fidelity polymerase because otherwise you have some risk to introduce mutations.